Usability is making your site easy and enjoyable for your users.
Frames are not acceptable in any application, and the use of frames causes users to be frustrated. Please refrain from using frames.
If you wonder why you are having trouble book-marking that link or you run into weird and complicated navigation schemes or you experience unusual performance issues, chances are frames are involved. Say no to frames. Frames are out-dated and no one should be developing them.
If you have a site in frames, please remove the frames. Time, energy and money is wasted. Frames are no good for anyone on the web.