Hey Alan, Just to let you know you have posted in the Bearshare Forum.
As far as the porn goes, P2P means that you are sharing files from other hosts computers, so there is really no way to police what someone is sharing. There is no servers so you just have to be careful and always use Bitzi. Here are a few other tips.
How to use Bitzi Fake files showing up in search results How to find music(tips for movies, too)