how is the owner leaching anything?
the person is still coming here, still seeing Davids site etc.
and lets face it, it's not like they are likely to get more traffic to their site...
and the headers/bindings are set up so that this site is shows as teh default page, even when you just browse by IP,
I'm guessing that's by design rather than just an accident since Davids hosts of the sites on the same server, and if he wanted a blank page to show up he could just assign a specific binding for the header computerforums.org and www.computerforums.org
... without messing about with PHP