I'm not sure how official this is, but apparently Google is going to start treating subdomains the same way they treat subfolders on a site, at least in the serps. Any given site gets a maximum of two listings in a search, but apparently people have figured out how to monopolize the top ten because, up 'till now, a subdomain has been a different site.

That will be interesting. I wonder what they'll do about blogger.com, wordpress.com and other similar sites. Perhaps they've developed an algorithm that can detect relationships between the subdomain and the domain; or maybe they'll have a section in Webmaster tools where you'll be able to tell Google how to treat your subdomain. Of course this is all just pure speculation for now.

I think this is only guess work, but people seem to be talking about an exception for Blogger, Wordpress, and other sites that host things for the public on a subdomain. I haven't seen cases where a lot of wp subdomains come up in a search, but it's entirely possible, and those actually are different sites.

Found a report from PubCon by Barry Schwartz (RustyBrick)

http://searchengineland.com/071207-090257.php

http://www.mattcutts.com/blog/subdom...ubdirectories/

That's really interesting. Thanks for sharing.....

Originally Posted by chrishirst

http://www.mattcutts.com/blog/subdom...ubdirectories/

Thanks, Chris! From the horse's mouth...

This change doesn’t apply across the board; if a particular domain is really relevant, we may still return several results from that domain. For example, with a search query like [ibm] the user probably likes/wants to see several results from ibm.com. Note that this is a pretty subtle change, and it doesn’t affect a majority of our queries. In fact, this change has been live for a couple weeks or so now and no one noticed. The only reason I talked about the subject at PubCon at all was because someone asked for my advice on subdomains vs. subdirectories.

I've been keeping my main site at forrestcroce.com, but also blog.forrestcroce.com and forums.forrestcroce.com, which I never did anything with. If you look at the main, ugly site, and the blog, they look nothing alike, and they're very different in a lot of ways. It really doesn't make sense to use subdomains versus folders. Especially since I'd ultimately like to put my main site on Windows and run asp, but, naturally, want to keep my wordpress blog.

I don't think this will actually affect the traffic I get ... I've been trying to cover different topics on each site, so they don't really overlap in the serps. Still, running an active subdomain, I've been curious.