brotherhood_of_LAN - 6:59 pm on Jul 27, 2010 (gmt 0)
This fairly recent discussion [webmasterworld.com] may shed some light on that front.
From tedster's post
As far as ranking goes, it's really not going to matter in my view. A few years ago, subdomains were treated more like a separate website by Gogole, but not today.
So it's not worth any agonizing - just pick one and then develop as technically sound a system as you can muster.