I'm having some problems with my login to the Commons -- I visit the homepage and log in. The menu bar shows me as a logged in user, and my user avatar appears on the homepage as a recent visitor. But when I visit a Commons subdomain, it's as if I never logged in (I was trying to go to the dashboard of one of my blogs). When I return to the homepage, it looks like I never logged in.
I am on a new computer, but I used the Mac migration tool to migrate my settings over from a previous computer, so I don't think my browser/cookie settings are any different than they were before. Can you please play around a bit and see if you can replicate this issue? If not, maybe it's just my new computer. Thanks for checking.