I'm using Firefox if it matters. I've been logged on on this site on my wife's Mac for many months (I guess it uses cookies to keep the login info). Today when reading unread messages since last visit, after reading several pages worth, it demanded I log on to get to the next page of messages. I did so, then a few pages later it did it again and I had to log on again to continue. At least it didn't lose read message pointer, like it has often done when timeout problems occur.
This has not happened before. Its been months since the last time I had to log on on this system, and that was due to a cookie cleanup.
Rich