We currently allow you to add any keywords you want. We'd like to eventually allow rather to communicate with things like tweetbot, so tweetbot can just pull from what you hate, etc.
I think what he's suggesting is that a topic-based filtering system would be more ideal than a key work based one. I don't want to have to spell out "block yankee's, tigers, indians, pirates, and giants". I just want to say "block all baseball", or "block all sports", and have the system know that posts about the yankee's, tigeers, indians, pirates, or giants are inclusive in these categories.