I think Steam Tags extremely useful. I like the tags "Procedurally Generated" and "Nostalgia" for example, which isn't a genre as much as it's small stuff which I enjoy.

I know some people dislike the tags because of trolls, but I feel the complete collection of 10 tags any game can have gives a fairly exact impression of what the game is. TF2 has tags like "class based", "free 2 play" and "hat simulator".

On the other side, Gone Home with tags like "Walking Simulator" and "No Gameplay" means I'd be best served just picking a movie.

Sadly I could not put "pretentious" as a tag. I know a couple of games which would deserve it...