Earlier quoted context omitted.
Further everyone's points about a form 1099 and how paying consumers doesn't make them a contractor, I also want to add that people as young as 13 were being targeted by these programs. Everyone under 18 is unable to sign a contract and therefore can't be a contractor, anyway.
Incorrect. People under 18 can enter into a contract with parental permission. Further, some stories have reported that Facebook says they acquired such parental permission for the minor participants.
Additionally, the minimum age for non-agricultural workers is 14 anyway, so even then they're in the wrong and can't legally hire 13-year olds as contractors or employees. There's also several other rules in the FLSA pertaining to workers under 18 including minimum wage. I have a sneaky suspicion $20 per whatever period it is (unless said period is a few hours) is going to be under that wage.
Not to mention there's a whole lot more can of worms being opened specifically around minimum wage and recording hours that I highly doubt either Facebook or Google were actively managing.