* quality: How do I know the quality of the work will be good? What happens in the case of disputes?
* reputation: How will you keep track of reputation of the workers? Odesk, Vworker, Ebay are marketplaces that do a decent job at filtering out spammers and bad guys. Where they lack is determining the difference between good and great. Everyone gets FIVE STARS or close to it for every job, unless it's completely bungled. This also creates a perverse pressure on the contractor. If an employer complains about the contractor publicly, the contractor quickly lose all work. Workers are thus pressured to satisfy out-of-scope employer demands so they get a five star rating and maintain their sterling reputation.