I would have to disagree about working best maybe it pays out the most sometimes. Google Adsense has a algorithm that searches for a 3% or more increase in account ad clicks per month. If you are a small website or business, and Google notices a 3% or more increase in your sites ad clicks you will receive a email like this:
Then they will keep all the money in your Google Adsense account, and banned your email address so they don't have to ever deal with you again.
If you want to use the banner factory model for making money I would strongly suggest using an alternative to Google Adsense. It might not pay out as much but you will at least get paid.
Another way people are making money from there games is buy selling virtual goods in game. Zynga uses this method on facebook, and out did EA Games in yearly sales last year.
This fricking happened to me. =/ Such BS. I could even take like a year suspension, but nope, banned for life.