As the name suggests, the earnings you make here are small. In fact, the money you earn by completing a task is insignificant. To make any decent earnings, you have to spend a lot of time on the tasks. And even then, there is no guarantee that the money will be enough.
Also, many sites that offer micro- jobs are unsafe. Be wary of viruses and malware that are built into such sites.
You could get paid in Bitcoins for completing small jobs. The jobs can be anything from re-tweeting to testing a website. Earnings are not lucrative, but they can be with a little diligence. A good place to find such tasks is on Coinworker.