I did at first, informing the world where I'm going and what I'm doing multiple times in the day, not my cup of tea.
I did start using it though, for news only tho. I follow espn, fox, certain apple sites, a very short list of actual people, the drudge report, washington post, huffington post, and some others. Just scroll through and save the articles i want to read and then bam right to the URL.
Thats the extent of my twitter usage.