The fact that people expect to be paid every time they do something nice for others says more about our culture than the whole Web 2.0 meme ever will.
There is no such thing as a free lunch. Even if people give away things for free, they usually expect something in return. Even if it is not money, it could be higher social status, a better place in heaven, or whatever. I don't think it is a problem.
Gift economy: http://en.wikipedia.org/wiki/Gift_economy
(This will all change very soon, when people are ready to start paying for a higher - and much more private and secure - level of premium service. You know, the Web will evolve to resemble the "regular' economy more and more, I believe..)