Nothing. The DHT is, has always been, and always will be, free of charge. I run it simply because I think it's a cool idea.
Your only cost (but that's not money going into my pockets!) will be the price of the registered version of DOOM, DOOM II or QUAKE as appropriate. Plus, of course, the intangible value of all the spare time that you're going to sacrifice in front of your monitor... but that's your own business ;-)
DOOM, DOOM II, QUAKE © 1993 - 1996 id Software
DOOM Honorific Titles © 1994 - 1997 Frank Stajano
$Date: 1997/07/06 23:29:18 $ UTC