Earlier quoted context omitted.
Twitter and facebook serve completely different purposes for me. Facebook is where I mostly interact with people I actually know in real life. I use twitter like you do, to follow interesting things. Then linkedin is people I have worked with. Each network serves a different purpose. I'd never pay for any of them though. I guess I should say I'd rather pay with my privacy.
Nothing wrong with using Twitter to meet people IRL. It seems weird to force those artificial boundaries on your social networks.
My soccer team (in general, some overlap obviously) doesn't need to know about my ballroom dance plans or my BJJ tournament or my date this Saturday. And none of them need to know about my family reunion plans (zero overlap), though I may post some photos to the public channel.
If the adoption in my friend groups had been higher, G+ seemed perfect for this to me. FB with effort, making groups that I invite people to. But I want it to be transparent. I want you to see me, not me(soccer) and me(ballroom). If you happen to be in both, it's the same, not separate spaces.