Actually, I *do* care.
Some of my friends communicate with BBM, but I don't have a blackberry.
Some use Facebook, which I hate. I'm losing touch with those friends.
Some use twitter, including me. Those are the friends I'm best in touch with.
Some even use email and phone, one even post, but I tend to forget to reply.
And you know what? This drives me up the wall. Social technology is meant to organise us and bring us together, not throw up barriers. The lack of interoperability is sheer petty bloody-mindedness on the vendor's parts. It'd be the easiest thing in the world to make BBM and iMessage talk to each other.