I've heard a few rumors of people not staying logged in on the main page. The browser reads your forum cookies, so follow these steps and it should work.

1) Make sure you have the 'remember me' option selected on the forums, so you don't have to log in each and every time.
2) Make sure you're not removing or editing the cookie set by the forums, either accidentally or though some cookie/ad blocker.
3) If you normally block all cookies, enable cookies from both http://forums.wireheadstudios.org and http://www.wireheadstudios.org . Phoenix and I ran into this bug during development.

If you still have problems with it, leave a comment. I'll be more than happy to help.