Pros
Learn about search advertising and platforms from the bottom up, which can come in handy if you go on to SEM work anywhere. LookSmart is small and you will be noticed, whatever you do. It's good training to learn how to get things done frugally or efficiently. Believe it or not, there are some smart folks there who want to be outside the GYM world as iconoclasts.
Cons
Market owned by big guys, and this is tough business which grows slowly. It's not clear where this tier or biz will end up.