Of course, you get what you pay for. Most people looking to hire on these sites aren't interested in quality; they want quantity at a discount. It works well for both them and the people doing the work at least in the short term. After all, some money (food) is better than nothing. I consider it a pretty base form of exploitation, though.
If you land a job making $5/hour, full time 40 hour weeks, that's $800 a month. A LOOOOT of people here would kill for that kind of salary.
Seems like there would be an opportunity for developers to donate laptops/hardware to people in developing countries who could use them to make money. I have at least 5 sitting around my office, only 2 of which are in use. I guess the logistics would kill it, but still.
It would be very hard to donate laptops here in Bolivia because of how this ass-backwards government handles importing goods and taxes when importing something.
What you make in a couple of days, they make in a year. It's mind boggling. Yes, cost of living is cheaper, but not that cheap.
On the plus side, you feel like you can make a difference in their life. If you're living there, you can pay them a great salary, without breaking the bank. Or if you're visiting, they might not expect tips, but hand someone $5 that went out of their way to give you a free ride on their moped, and you just dropped a few days income in their pocket.
Pick a country in the list on that page where the Per Capita Income is less than ~$4160/year. Most likely, in such a country, $2/hour is very likely going to put an individual at or above the median income (farther above, the lower the GDP Per Capita). $5/hr is a nice wage.
For comparison, the UN ranking of the US in this category is ~$51,000, and the median household income in the US is about $55,000 (per year).