Our classifier for parked domains was reading from a couple files which mistakenly were empty. As a result, we classified some sites as parked when they weren’t.
I apologize for this; it looks like the issue is fixed now, and we’ll look into how to prevent this from happening again. (Matt Cutts as quoted by Danny Sullivan)
Google reported that they made 53 changes to their search algorithm in the month of April. There were two more “panda” updates, and a “penguin” update. These updates appear to be directed at web spam. Many of the “mini-sites” and content sites created by domainers and parking companies are considered “web spam” – so be prepared to see traffic drop to sites that rely partly on Google for traffic.
A temporary problem also occured in April as some sites were mis-classified as parked domains. Google reportedly fixed this problem fairly quickly. The explanation:
None of this is really good news for people looking for easy domain monetization solutions, but it is probably good news for people searching for meaningful sites using Google. I don’t particularly want to land on a parked page when I am trying to get reliable information using a Google search.