The same thing confused the heck out of me. The only reason I can think of at this time (because I have not done enough experimenting) is that you did not check the box beside 'keep me logged in'. It seems that when you do a search and move to someone else's page, you get logged out of your own. Or, if you logged in while on someone else's page in order to vote or comment, that login only seems valid for that one action and you get logged out again after that. I've only been on here for a week, so that's the best I can do at this time. Sorry.