The Art of SEO, 2nd Edition

Spam Filtering and Penalties

Over time, it has become a lot more difficult to “game” the search engines and a lot easier to fall victim to a search engine penalty or outright ban. It is hard to recover from these.

Consequences can include ranking penalties, removal of the site’s “voting” power (i.e., ability to pass PageRank), incomplete indexation (i.e., a partial site ban), or, worst of all, a total site ban.

Not even the largest corporations spending big dollars on Google AdWords are immune. For example, BMW had its entire BMW.de site banned from Google for a period of time because it created doorway pages—pages full of keyword-rich copy created solely for the search engine spiders and never for human viewing. To add insult to injury, Google engineer Matt Cutts publicly outed BMW on his blog. He made an example of BMW, and all of the SEO community became aware of the carmaker’s indiscretions.

Search engines rely primarily on automated means for detecting spam, with some auxiliary assistance from paid evaluators, spam vigilantes, and even your competitors. Search engineers at Google and Microsoft write sophisticated algorithms to look for abnormalities in inbound and outbound linking, in sentence structure, in HTML coding, and so on.

As far as the search engines are concerned, SEO has an acceptable side and an unacceptable side. In general terms, all types of actions intended to boost a site’s search engine ranking without improving the true value of a page can be considered spamming. ...