The update was beneficial to Google, not necessarily to its users. A lot of Google properties (Demand Media, anyone?) that are clearly content farms climbed up the rankings while good sites like Stack, DaniWeb, and yes...Experts Exchange got nailed. In DaniWeb's case, she got nailed twice by two different updates.
The problem here is Google is selling the ads and also determining the traffic to the ads. It's too much in one place and ripe for abuse and the abuse seems to be happening