Does it matter if he came up with it? I think brilliance isn't always in coming up with the idea. Often it is the ability to see one idea of many, the one that appears ordinary to everyone else, and zero in on it.
I'm going to agree with kolya3 in part, however. Ideas are good, but execution matters a lot more. Part of that's because execution means deciding exactly how to implement things, and that's where Facebook really signs. Everything works beautifully on a level I don't think any other site has reached. It's perfectly compact.
That's why I have the interest in Zuckerberg that I do. I'd like to know how much of Facebook's design philosophy is his, and how much is somebody else's. If it's his, then to be honest I'd forgive him for a lot of other shortcomings.
I google ThinkComputer and very little substance comes up. I google the book, and very little substance comes up. I honestly don't think you had much beef on the bones to execute or market, and that's why I believe Mark passed on working with you and others. After all, how many founders of Facebook were there? I don't think his intentions were to short you if he thought you brought significant value to the equation.
Certainly I wasn't there so maybe I'm making an ass out of myself with said comment, but it's how I see it from a 3rd party persecutive. And with that said, I think it's time for you to move on with your life and show the world that you're not a prototypical wantraprenuer.