Attented Collective Intelligence 2012. This was the first instance of this conference -- very well attended, and great talks. Collective intelligence is related to 'crowdsourcing', but broader, including remote work like oDesk.
I was on an MITCNC crowdsourcing panel. The panel had a good perspective of crowdsourcing from a number of different angles (I recall uTest was there, and I forget who else -- I'm writing this post half a year retroactively). Discussion included some talk about the potential for expert crowdsourcing with sites like oDesk, as well as the potential for 'crowdsourced education', where people may learn new skills in apprentice fashion doing jobs online.