I think he paid them all $1 for the task, with the added bonus of possibly getting $50 if they win. Why is that not nice? They got paid, and entered a contest. $1 for a HIT on Mechanical Turk is pretty good, especially considering the amount of work they needed to do here (which is not much).

$1 seems to be pretty great for this task. I just read some HIT descriptions, and there were A WHOLE LOT of "write 200 words for $0.03" jobs. Which really sucks if you ask me.

The funny thing is, every single one of those participants thought it was worth their time. They looked for something to earn money, and found this. They clearly thought the time/money tradeoff was sufficient.

If you can earn a buck doing what a lot of (generally wealthier, admittedly) people do for free, why not?

1$ is the salary for one hour work for a maid in Shanghai... And Shanghai is not exactly the cheapest part of China.

I've also seen people making 100k+ who can't follow simple instructions or be bothered to read requirements.

45RS to take a photo and post it online is a good deal. That buys you lunch (or food for your family).

Over 50% did not do the required task. A lot of people sent me a picture of their cat or something.

4 out of 50 is 8% not 12%.

You could run another HIT to get people to verify the submissions and reduce the error rate further.