When an engineer flaps his wings. As several people have already noted, Google has made some major changes in their most recent update. The changes appear to be an attempt to stop two phenomena: explicitly selling ads based on PageRank, and Google bombing. [..]
Unfortunately, the algorithm tweaks necessary to stop these two techniques have caused a wide range of collateral damage, apparently coming down hardest on medium-to-large sites that had previously been doing everything right (as far as page structure, link structure, accessibility, and general honest hard work putting together a usable and useful site). The Webmasterworld forums are alive with complaints and speculation [dive into mark]
