It seems that this specific update is somewhat more substantial than the previous ones. The consensus among the seo experts is that google is raising the bar on page rank. It is now harder to earn or keep higher page rank. So what are the actual changes?
First of all, it is important to wait until the new update is stabilized. It usually takes few days to feel the influence of a change. Nonetheless, here is my two cents on the update.
Two major changes are obvious: the way incoming links are calculated have changed and the value of these links have changed. The sites presented when checking for links using “link: www.extradollar.net” is different from the number that is presented when writing www.extradollar.net on the search bar and choosing “find pages that links to …”. Both numbers are significantly different from the links provided by Yahoo and, of course, from the real number of links.
In addition it seems that Google lowered the value of incoming links from directories. It is now harder to find incoming links from directories on the links pages. My feeling is that Google increased significantly the number of “poisoned words” that they look for around the link. These words, once found, make Google to ignore the link or give it a lower relevancy. Another possibility is that identical phrases around the links now cancel each other or lower their importance.
It may be just a gut feeling but if feel that after the last index, some links can hurt your rating. I have noticed that the rank of sites without links did not change or even improved, while sites with many incoming (but probably less relevant) links suffer a drop in rank.
It will be interesting to see the long term influence of these changes.