Good piece of analysis from danah:
Twitter - like many emergent genres of social media - is structured around networks of people interacting with people they know or find interesting. Those who are truly performing to broad audiences (e.g., "celebs", corporations, news entities, and high-profile blogger types) are consciously crafting consumable content that doesn't require actually having an intimate engagement with the person to appreciate. Yet, the vast majority of Twitter users are there to maintain social relations, keep up with friends and acquaintances, follow high-profile users, and otherwise connect. It's all about shared intimacy that is of no value to a third-party ear who doesn't know the person babbling.
Perfect for showing the sceptic that falls back on the inanity argument.
I suppose I just never got into it. Time factore maybe - always doing posts.
It's become a major driver of traffic to my blog - for me, they're complementary rather than competitive activities.