It's hard to know how to value the widgets that populate Facebook. But Inside Facebook, a blog that isn't affiliated with the social network, has an eye-opening survey on just how much some developers are making from their heavily trafficked applications.

According to the blog, the posting is meant to be a starting place to determine what various developers are making on a CPM basis using the different ad networks that serve the Facebook platform.

The data, which is self-reported, ranges from 4 cents per CPM using AdSense, to $1.50 per CPM using VideoEgg.

The blog is asking developers to submit their own data to help clarify the fiscal reality of the social networking space. So far, most advertisers have been critical of sites like Facebook, which have had a hard time turning their highly trafficked space into a bona fide advertising platform.