If you've ever felt like comparing how much money a "traditional" video game makes as opposed to how much a Facebook game makes, check out this chart. It makes for interesting/depressing reading.
Put together by game site IGN, it's very important to note that this isn't hard science. Much of the information depicted is not given out in detail by these publishers, so some of the figures - like the exact revenue for the Facebook games - are put together from market research data.
This means that while the chart will be in the right ballpark as far as these games are concerned, don't go splitting hairs (or putting much stock in the player bases, since one requires a $US50 purchase and the other often requires absolutely nothing).