Skype's popularity has been rising with quite a pace lately; even my father tried to convince me to use it. Skype is a decent program, in my opinion, but I don't know many people who use it, so I find it a bit useless.
I was already introduced to Skype (more than) three years ago. Two friends of mine were always using it, but considering the fact that I only knew those two (later one other joined to it) who used that program, I decided it was more of a waste to keep it than anything else. It did give some good and bad memories when I was in high school though.