I'm glad someone brought this up. When a developer (or artist, or musician, or other creative person) gives away their work for free, that is fine by me. But when they later hold out their hat and say, "by the way, I worked really hard on that and I'm a nice person, would you mind paying for it now?" that's when I feel like I'm being manipulated. If you wanted money for it, you should have just said up front instead of tossing the guilt trip in at the end.
I do appreciate Jeff's enthusiasm for technology and he's done some cool stuff. I would totally hire him for a consulting gig if I were in a position to do so. But he's part of this "give stuff away for free and beg for money later" culture that rubs me the wrong way.