I keep having to log back in every 5 minutes...what is happening on this forum???

When you log in do you click on "remember"

It's very likely that you have a cookies error on your machine. The answer to this is to clear your SF cookies (no idea why, but it seems to work better if you clear the relevant cookies manually, rather than blanket emptying them all) then restart your browser and try logging in again.

Been happening to me last couple of days,trying to send posts then find l've been logged out usually after 5mins or so.