The website does have a timeout feature to ensure privacy. If you take longer then 30 minutes to write a post you will get timed out. Some members type their posts in notepad and then paste the post in the text box if they plan to write a long post.
It happens to me once in a while. If you hit the "back" button on your browser it will take you to your page with all of the text you were typing. Copy ad paste it to Note Pad, log back in, and paste it back in and you're good to go.