Games, Games, Games

I was recently watching a discussion about Halloween, when someone mentioned playing Call of Cthulhu for Halloween.  I had to mention a game (Betrayal), which took me to Game Geek.

I've been there before, mind you, but I was just noticing the mechanic property of their games. This is a slightly awkward concept to introduce to a website, but it has great potential. It would be nice to set a user preference to suggest "I don't like memory", and to get a list of games you haven't seen before, rank well on the site, and don't involve that mechanic.

Then I wondered if role-playing games could benefit from the same concept.  Or, even better, game masters.  Or individual games.

I wonder what set of mechanics would cover enough of each of those levels to help people identify the correct systems, groups, and games to play with?