...the absolute worst search algorithms ever devised
searching for continuous string elements is almost always of time-complexity O(n^2), meaning that its slow and gets even slower for larger n at a geometric rate.
if this were the only problem with the search button on these forums it might still be acceptable to tell someone to use the search function. you might have to wait 10-20 seconds for your result back (depending on their server speed) but you'd find something and 20 seconds is probably still faster than waiting around several hours for a response to a new thread.
but thats not the only problem. the button is just outright broken. if i had to guess i'd say they never got it working fast enough to be acceptable and it was bogging down their server so much that it was making the other pages on the site load VERY SLOWLY. they probably just disabled it completely, but for some reason left the button there for cosmetic reasons.
just speculating of course. maybe a Stardock person will come in here and tell us whats really going on, but thats my shot in the dark from the perspective of a programmer who has no inside knowledge of how these forums are implemented.