Slightly dated article, but still might be relevant.
http://thequill.org/personal-finance/13-sites-offering-crowdflower-tasks.htmlThere are other sites (coinworker is just one of the channels sending tasks to contributors) which have a higher payout for the
same tasks. If you only want some bitcoins, you could consider doing these tasks at other websites, getting paid in USD and then buying some bitcoins with USD. Might be more profitable than doing these tasks at coinworker for bitcoins.