Maybe I am wrong, but I think this is common knowledge.

If you log on to the site and you DO NOT check the "Remember me" box, you will be logged off after 15 minutes (I think it's 15) of inactivity.

If you don't want to have to log on constantly you can check that box.

If you want to log off sometime in the future you simply click the "Log Out" on the navigation bar. You'll see "Log Out" to the far right of the nav bar.

I use both IE 8 and Firefox. They both have tabs. I just leave xjtalk in a tab and when I want to check for anything new, I just go to the tab and hit the "New Posts" on the nav bar.