Louis Liem reports on a change with the Google Algorithm. Google seems to have changed the way they are treating subdomains in the rankings.
The article appears at Bukiki.com and includes quotes from Matt Cutts on the changes and what webmasters should expect with regard to subdomain rankings.
It’s likely you’ve seen all the change you are going to see since they’ve already gone forward with it. And since subdomains are supposed to be vastly different information than the information on the main domain and other subdomains anyway, this won’t affect most people.
The change was a result of people complaining about getting several results for a single domain on some long tail searches.
Overall the change should not affect a normal site’s rankings in any meaningful way. On the other hand, there are surely some spam site operators out there that are worried if they are using subdomains to game the system precisely to show up with multiple listings for essentially the same content.
This should take care of those knuckle heads!