I've been using Twitter for several months now. [I have ~25 people I follow and about the same number follow me. I post at least once a day and I've used it to learn more about people I already knew from work, and gotten to know people with whom I've spent less than 48 hours in person. I don't have it on my cell phone, but I do check it fairly regularly when I'm online.]
Although I have no idea what the company's business plan is (probably to be bought by Google or Yahoo), it's interesting to me that so many people are asking themselves how to use it (or dismissing it as overwhelming and/or naval-gazing). If we see it as a slightly different method of keeping in touch with other people, with people we're interested in for a variety of intellectual or personal reasons, then good. Why the hand-wringing or defensiveness about it I see from so many bloggers (many of whom I really respect)? [For example] Is it that it's really hard to explain to people who aren't on it?