I'd recommend freelancer.com/odesk/elance or any other dedicated market place. Freelancer.com i.e. allows very focussed searches via projects, you can specify the skills, timeline and all requirements and usually you get tons of very qualified bids in less than 24-48h.
Yes, but I'd far rather work with/for someone I met through Hacker News (probably, in general, I did actually find a great guy through oDesk). I've found some great work through these HN posts before.
Definitely for seeking work those sites do tend to be mostly a race to the bottom, you wouldn't believe the silly small amounts some people bid for projects (and how often they get chosen based on that).
