Sometimes SEO experts go too far in their desire to push their clients' sites to top positions and resort to questionable practices, like keyword stuffing. Keyword stuffing is considered an unethical practice because what you actually do is use the keyword in question throughout the text suspiciously often. Having in mind that the recommended keyword density is from 3 to 7%, anything above this, say 10% density starts to look very much like keyword stuffing and it is likely that will not get unnoticed by search engines. A text with 10% keyword density can hardly make sense, if read by a human. Some time ago Google implemented the so called “Florida Update” and essentially imposed a penalty for pages that are keyword-stuffed and over-optimized in general.

Generally, keyword density in the title, the headings, and the first paragraphs matters more. Needless to say that you should be especially careful not to stuff these areas. Try the Keyword Density Cloud tool to check if your keyword density is in the acceptable limits, especially in the above-mentioned places. If you have a high density percentage for a frequently used keyword, then consider replacing some of the occurrences of the keyword with synonyms. Also, generally words that are in bold and/or italic are considered important by search engines but if any occurrence of the target keywords is in bold and italic, this also looks unnatural and in the best case it will not push your page up.

Doorway Pages and Hidden Text

Another common keyword scam is doorway pages. Before Google introduced the PageRank algorithm, doorways were a common practice and there were times when they were not considered an illegal optimization. A doorway page is a page that is made especially for the search engines and that has no meaning for humans but is used to get high positions in search engines and to trick users to come to the site. Although keywords are still very important, today keywords alone have less effect in determining the position of a site in search results, so doorway pages do not get so much traffic to a site but if you use them, don't ask why Google punished you.

Very similar to doorway pages was a scam called hidden text. This is text, which is invisible to humans (e.g. the text color is the same as the page background) but is included in the HTML source of the page, trying to fool search engines that the particular page is keyword-rich. Needless to say, both doorway pages and hidden text can hardly be qualified as optimization techniques, there are more manipulation than everything else.

Duplicate Content

It is a basic SEO rule that content is king. But not duplicate content. In terms of Google, duplicate content means text that is the same as the text on a different page on the SAME site (or on a sister-site, or on a site that is heavily linked to the site in question and it can be presumed that the two sites are related) – i.e. when you copy and paste the same paragraphs from one page on your site to another, then you might expect to see your site's rank drop. Most SEO experts believe that syndicated content is not treated as duplicate content and there are many examples of this. If syndicated content were duplicate content, that the sites of news agencies would have been the first to drop out of search results. Still, it does not hurt to check from time if your site has duplicate content with another, at least because somebody might be illegally copying your content and you do not know. The Similar Page Checker tool will help you see if you have grounds to worry about duplicate content.

Links Spam

Links are another major SEO tool and like the other SEO tools it can be used or misused. While backlinks are certainly important (for Yahoo backlinks are important as quantity, while for Google it is more important what sites backlinks come from), getting tons of backlinks from a link farm or a blacklisted site is begging to be penalized. Also, if outbound links (links from your site to other sites) considerably outnumber your inbound links (links from other sites to your site), then you have put too much effort in creating useless links because this will not improve your ranking. You can use the Domain Stats Tool to see the number of backlinks (inbound links) to your site and the Site Link Analyzer to see how many outbound links you have.

Using keywords in links (the anchor text), domain names, folder and file names does boost your search engine rankings but again, the precise measure is the boundary between topping the search results and being kicked out of them. For instance, if you are optimizing for the keyword “cat”, which is a frequently chosen keyword and as with all popular keywords and phrases, competition is fierce, you might not see other alternative for reaching the top but getting a domain name like http://www.cat-cats-kittens-kitty.com, which no doubt is packed with keywords to the maximum but is first – difficult to remember, and second – if the contents does not correspond to the plenitude of cats in the domain name, you will never top the search results.

Although file and folder names are less important than domain names, now and then (but definitely not all the time) you can include “cat” (and synonyms) in them and in the anchor text of the links. This counts well, provided that anchors are not artificially stuffed (for instance if you use “cat_cats_kitten” as anchor for internal site links this anchor certainly is stuffed). While you have no control over third sides that link to you and use anchors that you don't like, it is up to you to perform periodic checks what anchors do other sites use to link to you. A handy tool for this task is the Backlink Anchor Text Analysis, where you enter the URL and get a listing of the sites that link to you and the anchor text they use.

Finally, to Google and the other search engines it makes no difference if a site is intentionally over-optimized to cheat them or over-optimization is the result of good intentions, so no matter what your motives are, always try to keep to reasonable practices and remember that do not overstep the line.