You can use the junk filter
http://www.gnutellaforums.com/showth...ng+junk+filter

Tools > options > filters > keywords and you can add certain words which you'd like filtered out (eg "sponsored", "buylegalmp3" & any keywords for porn). You can also tick the 'ignore adult content' box, this should stop a lot of porn from coming up in searches. Just remember to 'apply' to save changes