I think Wired has nailed a key reason microblogs work :
When I see that my friend Misha is "waiting at Genius Bar to send my MacBook to the shop," that’s not much information. But when I get such granular updates every day for a month, I know a lot more about her. And when my four closest friends and worldmates send me dozens of updates a week for five months, I begin to develop an almost telepathic awareness of the people most important to me.
It’s like proprioception, your body’s ability to know where your limbs are. That subliminal sense of orientation is crucial for coordination: It keeps you from accidentally bumping into objects, and it makes possible amazing feats of balance and dexterity.
Twitter and other constant-contact media create social proprioception. They give a group of people a sense of itself, making possible weird, fascinating feats of coordination.
One of the other cool things about vox and pownce is that posts can be private or public. The idea seems to be that the "next web" is all about transparency- I’d be wiling to bet it’s about intimacy and privacy. Half of the posts on my vox blog are for friends only- same thing for pownce. Twitter is for all, and is a fun experiment, same thing for Techbytes.
I’m starting to appreciate that the platform that provides the best communication tool, while allowing users to determine who sees what will be the winner…