That sounds obnoxious. I'm not having the same issue so would it be possible to confirm which browser (and version) you're using?
As a first step I'd recommend clearing all the stored cookies/cache in your browser then trying to log in again, to see whether it works properly after that. Something might be stuck somewhere with the wrong timestamp.
I've just checked in Chrome (exact same version on OS X) and I'm having no trouble staying connected in chat or in the forums. However, I think that was my first time signing in with Chrome on this computer, so I didn't have anything stored.
Does it do the same in Incognito mode?
Another thing to try if you have a second user account or Guest login available is to see whether you can use the same net connection, computer and Chrome install to access the site as another user - which would point to it being a local setting or file.
Sorry, delayed response. I use chrome. i think it might be related to adblock. turning it off keeps me logged in without too much of an issue. I'll keep myself logged in for a while and see if it sticks, but that might be the cause.
EDIT: ok, it's not worked. clearing cookies hasn't sorted anything either. I'm trying to see if there is anything else affecting it, but i can't see much.
That's a shame. I don't think there's anything more I can do on the server side to fix this - it seems like some kind of cookie problem on the local computer for both of you. If you get a chance to try the things in the fifth post in this thread I'll have another think :/
(If anyone else is reading this and having the same issue without being able to log in for long enough to post about it, please feel free to send me an email.)
I'm kind of curious to see if it's just a cookies issue. It's happening to me on Steam as well. Part of me thinks it's some iteration of packet loss, but i can't say. I've been ok with staying logged into the forum, chat won't keep me there.