I found this to be a pretty good general list:

http://thenextweb.com/entrepreneur/2011/05/25/the-9-types-of...

Of course there are sub types under each of these 9 categories and combinations, but its a start

I think the most common are probably Ad-supported, Subscription, and Freemium(especially for games).

As we're seeing with all the issues being brought up about Facebook, Twitter, and Zynga, these current models do not always work. And even when they do, there are still issues. There is huge potential right now for new revenue models, so I would recommend getting creative with how your idea could potentially make money. If app.net succeeds, then there will be more of a transition to subscription services versus free, ad-based services. Currently though, the majority of users prefer free. The challenge is figuring out how to make money from them, which is why ad-supported services are so prevalent.

So try something new. And don't be afraid to ask for money.

Here are a few useful resources:

Standard Forms of Value from The Personal MBA: http://book.personalmba.com/12-standard-forms-of-value/

Outline of 25 forms of profitability from The Art of Profitability by Adrian Slywotzky(as outlined by Derek Sivers):http://sivers.org/book/ArtOfProfitability

Hmm... The closest thing I can think of is the book "The Personal MBA" by Josh Kaufman.

In the book he talks about the "12 Standard Forms Of Value". These 12 forms of value cover pretty much any business you can possibly think of. In other words, if you're in business and making money, you're using at least one of these twelve methods.

Take a look at this: http://digitalenterprise.org/models/models.html

There are some examples in there, though a few are a bit dated.

Thanks for all of the great ideas!

I'll pore over these lists and keep brainstorming how each of them might apply to the idea.

This is a good question. I look forward to responses.