I think it's in the eye of the beholder. A number of people seem to be against it on the basis that they donate to charity already and don't need an attention seeking exercise to prove it. Fair enough.
I found myself nominated on the weekend and took part, it was a good laugh actually. I also donated, but to a smaller local charity instead.
Following this I nominated 3 pals, only one of which did it. I have no problem with that, to each their own.