U_SessionId is used for authentication for that individual browser session. When a user logs in, a session id is generated and put into the sql table. This session id is then used for each call to authenticate() to make sure it's a valid user. When a user logs out, the session id is cleared. If they don't specifically log out it still gets reset the next time they login.

U_TempPass is used when a user requests a temporary password. This field gets populated with a temporary password that they can use to login 1 time. This makes it so if someone else requests a temporary password for another user, the user can still login with the original password since they didn't request the temporary themselves.

Yes, w3t_Online only stores data that is used for display when someone visits "Who's online"

-------------------
Rick Baker
UBBThreads developer