For developers specifically, I feel like Stack Overflow Careers our jobs or whatever) is about a million times better than LinkedIn, but it doesn't have the social aspect, I guess.
Haven't used it while looking for a job, but we've used SO to post and have not had good luck. Craigslist yields better results for a mobile dev in Portland, and costs one tenth of SO. Additionally my business partner and I received no less than 20 unsolicited recruiter and contract services spam emails each, and I wasn't even on the job posting!
> I wasn't even on the job posting!
Maybe they found you on LinkedIn :)
I appreciate that it's not 'social'. I don't think I'd use it if it resembled a social network.