Not too long ago Matt Cutts posted a blog entry named PageRank Sculpting. This article notifies search engine optimizers that the way PageRanks flows between web pages has changed.

Before the change, if a web page had a PageRank of 5 points and linked out to two other pages, this PageRank would be divided in two and parsed over to the other two pages. You can see this very clearly in the image of Matt’s article.

The rel=nofollow attribute is an HTML attribute which, when added to a link prevents the PageRank to flow over to the other pages. So a page with PageRank of 5 points that links out to two other pages which has two rel=nofollow attributes added to them will not parse PageRank to the other pages.

The result is that the PageRank of 5 points are deliberately kept on the original page, giving that specific page an advantage over the other pages in the web site when getting ranked by Google.  This is called PageRank sculpting and it’s one of the tricks that experienced search engine optimizers use in order influence rankings.

Truthfully, it was only a matter of time before Google would put a stop to this and Cutts even stated that they thought people would notice a change would be coming. The reason behind the change is of course because eventually, practices such as PageRank sculpting would influence how relative the search results are because ranking power is directed to certain pages and kept away of others deliberately.
The lesson here is not new. We’ve seen this time and time again.

If you want to keep being successful at SEO and keep your traffic coming you need to not only understand the search engines, but also need to think like the people behind the search engines.

Their aim is to provide users with relevant search engine results.  It means that any seo practice which eventually might influence the quality of their services will be dealt with in this way.