Twitter allows only very short posts. I see no point to it at all. My take is that it is for people with attention deficit disorder who can't read more than 20 words without losing track. People who love it would probably say that I am just too long-winded or too undisciplined to take advantage of the opportunity to post terse, info-rich updates. (Of course, most people tweet stuff like "Now I'm eating a bagel at Moishe's.")