the law is pretty specific on this. Shap does not have the right to be suing people so I have no idea what his lawyers advised them:
http://www.uspto.gov/trademarks/reso...m/guide299.jsp
It's all right there... The only mark you can even try to claim is a mark specifically named the absolute name of the domain. You can not try and take something that has additional letters in the domain regardless of what they are. That means I can legally own iSexTube.com if I wanted and there isn't shit anyone can do about it.
Even phonetical differences aren't covered under a mark (sextoob.com, sekstube.com, whatever)...