Some data points. Took a poll around our office (it was kind of thin because of the holiday) and of the 4 devs that responded and said they use SO, all 4 said they don't actually care about or pay attention to the points, they just use it as a source of information.
The vast majority of people using stack overflow are simply consuming questions/ answers they have arrived at via a Google search. These people won't care about points but it doesn't tell us anything about the motivations of those that are regularly answering questions.
Here's a data point from another end of the spectrum: I've provided more than 1000 answers. I love it.
If there were no StackOverflow I would use other means more: Usenet/mailing lists, irc.
I don't find it offensive that someone tries to reduce my motivation to accumulating points. It is just another example of "someone wrong on the internet".
