Because I started with Twitter so early, I know something that later-comers might not.
Twitter was better when there were fewer people there.
Before it was so random. Before there was so much spam. When everybody on Twitter was likely someone I wouldn't mind hearing about, and from.
It's probably why people are liking Google-Plus now. It's small. Approachable. Filled with people you know.
If they make Twitter too unpleasant with ads (sponsored tweets) it could fracture into a Twitter for tech, a Twitter for NYC, perhaps a Twitter for the Lower East Side, even. A Twitter for me!
I had this thought when I looked at how competent Twitter is these days. But the question is, do we really need something that does what Twitter does. Do I need a service that can serve people with 6 million followers? (No, I don't follow anyone with that many, and I myself have less than 40K followers.) Do I pay attention to the tweets of even a fraction of the people I follow? (No, no one could.) With Twitter, I think there's no doubt that it would be better if it were smaller.
But who cares as long as there are no ads. But they're coming, soon. Maybe they'll solve the problem by letting people pay them, say $25 per year, for an ad-less Twtter.
That would help keep it from fracturing.