I think Jeph made the Vespavenger site just to prevent someone else taking that name. According to Alexa, that site was created and peaked in traffic at the same time Jeph was using that arc.
I'm reminded of an obscure FCC regulation that stipulates if you mention a fictional web domain on television or radio, you are responsible for the content of that domain. Perhaps this applies to the internet too. So if someone purchased vespavenger.com before Jeph made the site and after he showed the Coffee of Doom crew checking it out, then whatever they put on it is Jeph's responsiblity. So if they put child porn on it, Jeph would be responsible for child porn.