That´s not my idea but a vbb use it where i have a moderator, i don´t know that thing work on a ubb but let me see what our super hackers here say
Ok it´s a simple thing , good boards have many members and when too many users on the board then crash sometime the server (our board have a own server and we host another ubb too) , sometime when too many surfing around our server slow down, some webmasters know that is a big problem. Now the Hack.
ok i say i set a limit of 40 users that surf on the board, comes more stop the hack the new guests or members and say them that the maximum users on board plz retry some time later. The server have still the hits board must not load for 70 ppl or so the cgi´s etc.
I think the Problem is now that a vbb use mysql, here must the ubb use some method to identify the users that was on the board or it stops all users.
1 Idea from me is who is online use the ip to identify the guest´s etc the hack must do that too or it requires who is online.
I think that was enough now, i don´t see somewhere that hack or the idea.
*Sorry for my really bad english I hope it´s good enough too understand what i mean*