Writers' Wednesday: To Tweet or Not to Tweet?

OK, fellow writers (and readers!) out there: a question for you: do you Tweet? That is, if you're an author, do you use Twitter as a method of social media communication/sales and promotion ~ and if you're a reader, do you follow favorite authors?

I'm taking a month-long course over at Savvy Authors on Social Media for Writers, mostly to figure out how to use what I do have in place more effectively - but also to find out if I should be using Twitter and if so, how the heck to go about doing it.

So I'm interested...if you are an active Twitter member, what do you like about it? What do you most use it for? How often do you Tweet, and is there anything that really turns you off about how other people use it?

I'd love to know!