The main reason for adult versus shared is that MOST adult content sites take a lot more bandwidth and resources than a normal shared server would support. The second reason is more of a concern for our users. IF something happened on the DNS and wires got crossed, the last thing we'd want is to have a website pointing at an adult site by accident. Can you imagine the face of a pastor going to their site to insert the days sermon only to be greeted by a bondage page? Bandwidth and CPU usage are the main concern.

Our VPS servers are located in a different data center and their AUP does not permit adult material, so we have restrictions on there too.