If your game gets sponsored but you get to keep the rights for advertising, you can make a lot of extra residual income from MochiAds. So much that in some cases I have heard about is the developer has made more money from Mochi than sponsors.
One extra feature from MochiAds is the 'Traffic Sharing" program which lets you place your own ad and put it into the system. Your ad gets more views the more popular your game is. I was looking through the forums there and some people have got 6-7 thousand clicks, all for free and you can link that ad back into your games so you get even more money.
If you have a website you can join the publisher section as well which gets you 10% of the income, I will add more to this when we get to creating flash games portal/website.