I hate the way SO only remembers you for a week or two, so when you return, you have to login, going to a separate screen and so on. Why do they have to make it so hard? What's the advantage in forcing frequent logins?
Yeah, I know I should find some other StackExchange site, go there, create an account there, login there, and post this complaint there - but you know, that's just more of the same problem. </rant>
Er.. what? We can't reproduce this, and there are sites in the network I don't visit very often, too.
Please note we did force logout globally, network-wide in April 2010 (to mandate emails for Google GMail OpenIDs) and September 10th 2010 (to enable global auth for all users).
Also, we delete any sessions older than 4 months as a matter of course.
So if you visit VERY infrequently, you might run into one of those.
There was a recent forced logout on all stack* sites due to changes in the way cookies are handled. If you haven't visited in a while, that could be the cause of it.
Yeah, I know I should find some other StackExchange site, go there, create an account there, login there, and post this complaint there - but you know, that's just more of the same problem. </rant>