While I normaly agree some hacks do justify their own sites, with some of the larger ones it makes it easier on the end user when that hack has its own support forum that is searchable. Instead of spending alot of time reading a big thread they can get exactly what they need quickly.
It is really a hack by hack basies, some hacks are to small for their own dedcated forum imo, but if the author wants to have his own space to show off his work and support his users there is nothing wrong with that ethor.
Now these pop up 'vBorg' clones are a differnt story, I see them as un-nesscary, but if a group of users wishes to do that there is not much you can do to stop them, besides if someone wants to make a site about vB hacking who really cares? It is there money to spend anyway, as long as they compliy with the license agreement they are fine, just like the lot of us
In the end I don't think it hurts this community much, it has its up and down's but you still don't see much of a slow down in the number of hacks released.