Intro
There are 2 types of search engines: Search Engine Spiders and Search Engine Directories. Each search engine uses unique criteria for "ranking" sites - this "ranking" determines their placement in the search engine results page (SERP). Spider-driven engines use robots to spider sites on the Internet. Robots "crawl" each site and "score" pages based on relevancy. Directories have humans that check the sites - rather than robots. Some engines score the index page while others score individual web pages.

The goal of search engine optimization (SEO) is to get higher rankings. This is done using a two-step process. The first is to use industry information that allows professional optimizers to understand what these robots are looking for. This is a complex process because a Web site's placement within a spider driven search engine is derived from hundreds of variables such as link popularity, click popularity, keyword density, Web site themes and more. The second way search engine optimization professionals optimize sites is to eliminate/reduce on-site techniques that can impede the search engine spidering process.

The topics mentioned below could either block search engine spiders form crawling your site accurately or ultimately get your site penalized in certain engines and/or directories. Take these into serious consideration when designing and/or optimizing your website.

SEO Topics Covered:

•  Duplicate Content
•  Doorway Pages
•  Frames
•  Cloaking
•  Link Farms
•  Design Blocks
•  General Spam
•  Overview

Duplicate Content

Creating duplicate content/mirrors/redirects might be one of the worst things you could possibly do if you want to succeed in the search engines. When search engines were first getting popular, you could simply point 10 domain names to the same Web site and they would all stack up on the same page of results for the same keywords. Meaning, if you ranked well with one phrase, all 10 of those sites would do the same. This was a burden to the search engines, so now they use very sophisticated algorithms to filter out duplicate content.

They examine all aspects of site structure, image names, and matching text. When too many of these areas match another web site it triggers a red flag, and the site is penalized. Beware of mirror sites, affiliate sites, or any other "cookie-cutter" web marketing service that promises big profits with little effort. Today's engines will remove or reject duplicate content, so this usually leads to failure.

If you want to thrive on the web make sure your site has original and unique content. The safest way to get top search engine placement is to produce real content.

Following are three examples of the use of duplicate content:

• Mirrored Sites: Mirrored sites occur when the web site sits in one folder on a particular server, has one IP address, but 2 different domains pointing to the same folder. So, when you type in the two different URLs they both bring up the same site. This is a horrible scenario for search engines. Google® sees this as being tricked, rules it as duplicate content and will penalize the site. They can choose to only index one of the domains or not list either of them.
• Cloned Sites: Sites that are cloned sit in two different folders; have two different IP addresses and 2 different domain names. This scenario is generally ok with the search engines as long as at least 40% of the site content if different from the other. Again, engines will not stand for duplicate content and will penalize the site if they are not different. The Database of products can stay the same as the long as total look and feel of each site is different.
• Redirects: Pointing multiple domains to one site seems to be very popular these days. This is done by registering multiple domains and redirecting to one main domain name. Again, this can cause problems because the engines think you are trying to trick them by taking them somewhere else. They treat this just as a clone, consider it duplicate content, and can penalize the site. If you must have multiple domains, use a 301 redirect on all secondary domain names pointing to your main URL.

Doorways
Many believe doorway pages are an essential aspect of an effective search engine optimization. In an effort to improve rankings, however, some marketers have spammed the search engines with doorway pages, generating multiple pages with little information, making it a topic of much controversy. Search engines have responded to this practice, and are now much stricter in their rules and requirements. Filters have been created to block the "spammers rendition" of doorway pages.

A doorway page, or gateway page, is an alternate entryway to a web site created in the interest of obtaining a top ranking on particular keyword phrases in a major search engine. Doorway pages are often hosted at a different location than the original site. In other words, a new domain name is registered (usually one that includes keyword phrases) and the doorway page is created on that domain name, with links to a destination page on another web site. Typically, these pages match the look and feel of the original site. You should avoid registering a large number of domains with this tactic because it could be considered spam by the search engines and could get your site penalized.

Frames
Frames present some great possibilities to us from a web design standpoint, but they should be avoided if at all possible when it comes to search engine optimization and getting your site listed in the search engines. Many spider-based engines cannot crawl through them, and specific coding is necessary to make them readable by the engines. This coding is viewed as spam amongst most of the search engines. Spiders want to be able to read and view everything that the visitor of the site can. However, if your web site does use frames make sure that you take advantage of the content area on your web site that doesn't utilize frames. It's a very powerful section of the site, and if used properly it can result in some excellent rankings. Nevertheless, frames do pose unique problems and spiders cannot read them. The good news is that despite many of the limitations frames pose, many frameset 'issues' can be turned into frameset 'positives.'

So, if you are going to use frames for search engine optimization make sure that you use them wisely. You can still create a pleasing interface on a two-frame set by specifying the dimensions of your top or bottom frame as 5 to 8 pixels or 5 to 8%. That should help you avoid the spam filters.

Cloaking
Cloaking, also known as spoofing, is a method of web page delivery where different pages are served from the same address, no matter if the visitor is a human or a spider. In other words, browsers such as Internet Explorer are served one page, and spiders visiting the same address are served a different page, usually an optimized page. There are two methods of delivering cloaked pages - IP address and Agent name.

There are two reasons people use cloaking techniques.

1. Since viewers never see the page that is viewable to the spider, the code cannot be stolen. In highly competitive markets the ability to conceal code from the competition can be an extremely powerful advantage.
2. Since a human visitor never sees the page that is served to the spider, the spider page does not have to be aesthetically pleasing. As a result, it can be optimized with every trick in the book.

By using cloaking, nobody sees the page except for the spider. That gives cloaked pages an extremely powerful advantage over web pages that were optimized to accommodate a professionally appealing design.

But, cloaking may be one of the most frowned upon techniques among all engines. Filters will pick up pages like the following in no time:

• IP Address Delivery:
  An Internet Protocol Address is a numeric address, which identifies your connection and presence on the Internet. In addition to sites having IP addresses, so do the spiders. Since you can 'sniff' for the IP address when someone visits your site, you can use this data to push specific pages to the spiders. This method is more complicated than Agent Name Delivery because it requires you to maintain a never-ending list of IP addresses and IP addresses change all the time with the addition of new ones. The advantage to IP Address Delivery is that someone cannot steal or mimic your IP address, making it impossible for anyone to see the code that is presented to the spider.
• Agent Name:
  Delivering a specific page based on agent name is a rather simple, but risky task. You simply utilize some code that says to basically take the visitor one place and the spider to another. While very effective, agent delivery is not a foolproof way to hide your code. Someone can easily use an agent-faking program to report his or her agent name as that of a spider when visiting your page. They will then see exactly what is being served on each page.
  
  Also, some browsers offer the user a choice of User Agent variables to submit to any web site they visit. Consequently, someone might spoof a search engine spider's User Agent variable to detect whether you are using cloaked pages. Whatever the case, any time you use cloaking you take the chance of being labeled a spammer, a very good chance to say the least.

IP cloaking is abusive in how it attempts to manipulate a search engine's index. Since IP cloaking is deceptive, search engines routinely purge IP cloaked pages and in some cases ban these web sites permanently.

Link Farms
Since so many engines use link popularity as an integral part of their ranking algorithms, many webmasters responded by joining link farms and stuffing their sites and others with as many links as possible. But, all links are not good links. In fact, bad linking strategies may get you banned from some engines.

A link farm is a network of web pages, which are heavily cross-linked with each other for the sole purpose of increasing link popularity. The web pages usually are in more than one domain or in more than one server. When a web site joins a link farm, it gets a link from each of these pages and in turn it also has to link back to each of those pages. This will then affect the link popularity of the site. But search engines definitely detect the link farms as well as the web sites participating in the link farms. Google®, for one, disapproves of link farms and labels the links they generate as spam. In fact, some sites get removed from the index altogether if they are affiliated with link farms or link stuffing.

Because of this, some webmasters have chosen to remove all links going out to other sites. That is an overreaction that decreases the site value to visitors and hurts the Web in general because cross-linking is a basic tenet of the Internet. Links are fine - even encouraged - if they are related to your topic, but link farms rarely provide useful content to visitors. If your site is selling cars, linking to car parts sites, car forums and other car related sites, is very safe and encouraged. You are only providing access to other sites that are of interest to your visitors. But, if you signed up with a service that promises to generate five hundred inbound links to your site only if you agree to add two hundred outbound links in return, then you are likely participating in a link farm.

Instead of linking to related information of value to your visitors, you are sending them to sites with non-relevant and useless information. Search engines will not penalize you for good, relevant links, but are quick to punish sites that try to spam them with unrelated links.

Spider Design Blocks
Despite the best efforts to make your site look unique and attractive, some of the web's most prized web design technology can be a major stumbling block for a search engine spider.
Flash Sites (or flash introductions) - while beautiful, cannot be read by a spider. Your solution options are to use an entrance page that is keyword text phrase intense, create a two frame frameset where one frame is only one pixel high and use the No Frames area, or to alternate the use of Flash and static HTML. Following are design attributes that block spiders:

• Frames - despite the unique design and product capabilities they present, can be a major problem for search engine spiders. Many spiders cannot read them at all. The quick solution is to utilize your No Frames content to optimize your page or stay away from them altogether.
• Image Maps - are something that can possibly pose a problem with some engines. If you plan to use an image map, make sure there are other links on the page (perhaps on the bottom), that link to your other pages.
• Password Protected Pages - are pages you probably do not want in the engines anyway. Just be notified, that like a human, the spider cannot enter any area that is protected by a password.
• PDF Files - usually provided by Adobe Acrobat Reader, present a major stumbling block to most spiders. Some engines (specifically Google®) are beginning to index these kinds of pages, but from a search engine optimization perspective this is one format that you want to avoid.

Search Engine Spamming
Search engine spamming is the use of unethical techniques for improving the position of a Web site in a search engine. In order to improve their position in a search engine, some Web site owners use spamming (unethical techniques) and in turn try to fool the search engines.

Each search engine's objective is to produce the most relevant results to its visitors. Producing the most relevant results for any particular search query is the determining factor of being a popular search engine. Every search engine measures relevancy according to its own algorithm, thereby producing a different set of results. Search engine spam occurs if anybody tries to artificially influence a search engine's basis of calculating relevancy.

The following techniques can be considered spamming:

1. Code swapping ("bait & switch")
   This means optimizing a page for high search engine position, and then swapping another page in its place once a top rank is achieved. This technique will not lead to a long-lasting search engine placement because filters have been implemented across the board to detect this.
2. Content Spam
   With the help of this spam technique only the search engines can view a particular part of the data in a web resource. Some commonly used content spam techniques are as follows:
   
   Invisible text - Hiding keywords within the background by using exact or similar font colors is one of the most common search engine spam techniques to date. This can be done by using tables or a background with a different color other than the real background for the site.
   
   Keyword stuffing - Another very popular search engine spam trick, used along with hidden text, is the repetition of keywords on the bottom of the page in very small fonts. Since the font is hidden, keywords are crammed into a section of the site with the intent of capturing the spider's attention.
3. E-mail spamming
   E-mail spamming means sending commercial messages to email addresses from unwanted and unknown sources. These messages can include, but are not limited too, chain emails, get-rich scheme messages and messages that contain adult related material.
   
   There are various ways of collecting email addresses. The easiest is to collect them from newsgroups. Newsgroups are a great source of information, but spammers collect email addresses out of the posted articles in the newsgroups with the help of special software. Email spamming can be used to generate links and solicit search engine submission services.
4. Meta spam
   In order to manipulate a search engine's relevancy algorithms, meta data can be used as a web resource inaccurately or incoherently. Following are the common Meta spam techniques:
   
   Unrelated keywords - In order to fool crawlers it has become a common technique to use popular keywords that are not relevant to the site's content. For the time being, one may be able to trick a few people searching for such words into clicking at the link, but soon they will leave the site when they receive irrelevant information on the topic they were originally searching for. This kind of search engine spam upsets both the search engines and their users.
   
   Hidden tags - The use of keywords in hidden HTML tags, for the most part, are considered spam to most search engines and will warrant penalization. These tags can include, but are not limited to: title, meta description, http-equivalent, comment, style, hidden value, font, alt, author, option and no frame.
5. No content
   If sites do not contain any unique and relevant content to offer visitors, search engines can consider this spam. On that note, illegal content, duplicate content and sites consisting of large affiliate links are also considered to be of low value to search engine relevancy.
6. Over submitting
   Each search engine has its own regulations on how many pages can be submitted at a time and how often it can be submitted. Submitting the same page more than once a month to the same search engine and submitting too many pages each day is not allowed.

Search Engine Optimization – Network Solutions® Overview
Search engines strive to provide the most relevant results to their users, but spam swamps their indexes with irrelevant and misleading information. Therefore, it is advisable to make no mistakes and stay clear of anything that could be seen as spam by the engines. Instead, focus on an ethical approach to SEO. Search engines will always react to the spam techniques when they become a big enough issue and they are affecting searchers. Banning is a last resort but has definitely been known to happen.

The following list will give you an idea of the basic "DONTS" for the search engines:

• Do not use text that is the same or slightly different color as the background to 'hide' keywords.
• Do not repeat the keywords in the Meta tags (use them only once), and do not use keywords that are unrelated to the site's content.
• Do not create a title like "web hosting, web hosting, web hosting." This is considered spam.
• Do not repeat the keyword to increase its frequency on a page (Keyword stuffing). Search engines now have the ability to detect this: they can spider a page and determine whether the frequency is above a "normal" level in proportion to the rest of the words in the document - this is also known as keyword density.
• Do not optimize a page for top ranking, and then swap another page in its place once a top ranking is achieved.
• Do not put misleading words on the page in the hopes of attracting visitors looking for another topic.
• Do not submit a page to the search engines that, once loaded, automatically redirects to a page of different information.
• Do not create a page that prohibits the user from using the browser's back button to return to the search engine results.
• Do not create "doorway pages."
• Do not submit the same page more than once on the same day to the same search engine.
• Do not put multiple instances of the Title Tag in the HTML code.
• Do not put pages of content in layers and position them off screen or practice the same kind of behavior by turning the visibility of the layers off.
• Do not use small or 'invisible text' in the page.
• Do not send query to a search engine with an automated 'rank reporting tool' hundreds of times per day.
• Do not purchase multiple domains and put duplicate copies of the web site on each domain.
• Do not participate in Link Farm programs.
• Do not submit different versions of the web site in the hope of getting multiple listings.
• Do not submit more than the allowed number of pages per engine per day or week. Each engine has a limit on how many pages one can manually submit to it using its online forms.
• Do not cloak.
• Do not support affiliate sites with the same or similar content but different site designs.
• Do not create a page that is stuffed with keyword content so far down the page that it is unlikely anyone will ever scroll down that far.
• Do not create a plain page specifically designed to rank highly, and then once indexed, upload a different page to your server.
• Do not put hundreds of 1x1 transparent .gif's on your page and assign them all the same ALT text. This is rather easy to detect.
• Do not use CSS to set the text size of a particular tag to 0% and then fill your page with 'invisible text.'

As you can see, there are a lot of ways to fool the search engines, but just about all of them are detectable - and that makes them very dangerous.

If you are serious about custom delivery to the engines, there is really only one way to go - and that is with a professional search engine optimization.