I've lost a three posts that I have posted that were of some value and were of decent size, but the forum times out and logouts way too soon. As well, when I hit the back button the post is gone. This is ridiculous, if you want people browse the forum and then make some posts. I don't know about other people but it's discouraging me from posting and getting involved with this forum.
If people aren't idle (visiting posts and so on) for 10-15 minutes than they shouldn't have to log back in when posting.