When Big Gunns goes into one of his long and very informative posts, he usually has to sign back in when he hits "post". One of these days all that valuable information that BG posts might be lost forever if he forgets to copy it. We wouldn't want that to happen now would we?
When you are signing in....there is a little check-box right next to where you are inputting your username and password. Click on that check-box (I believe it says "Remember Me") and you will stay logged in until you manually log yourself out or switch computers.