tweet or twitter?

Twitter, like Facebook, has become and integral part of our lives now hasn't it? For a significant number of people at least. And being the innovative people we are, new words and terms are coined. So words that are specific to Twitter: twitter/tweet, twittering/tweeting, tweeted/twittered, tweets.

These words are already pre-existing but Twitter has brought about new meanings to them. The dictionary meanings for those words are as follows:

twit·ter (twtr)
v. twit·tered, twit·ter·ing, twit·ters
v.intr.
1. To utter a succession of light chirping or tremulous sounds; chirrup.
2.
a. To speak rapidly and in a tremulous manner: twittering over office gossip.
b. To giggle nervously; titter.
3. To tremble with nervous agitation or excitement.
v.tr.
To utter or say with a twitter: twittered a greeting.
n.
1.
a. The light chirping sound made by certain birds.
b. A similar sound, especially light, tremulous speech or laughter.
2. Agitation or excitement; flutter

and

tweet (twt)
n.
A weak chirping sound, as of a young or small bird.
intr.v. tweet·ed, tweet·ing, tweets
To utter a weak chirping sound.

With twitter now, sentences like "I haven't tweeted anything today" or "Did you read her latest tweets" are very common. I'm wondering though whether tweet and twitter in Twitter context can be used interchangeably? I suppose they are. I always use the verb "tweet" but I know many people say "I haven't twittered anything today" instead of the sentence above. What about you guys? What do you think? Do you have preferences? And why?