If you're not near a keyboard or don't want to noodle around typing a tweet on your mobile, just leave a voice tweet, and Twitterfone will transcribe it (accurately in my case, even allowing for my sometimes impenetrable Yorkshire accent.) and then load it up to Twitter.
A pal of mine wasn't overly impressed saying he preferred to type his tweets, which is fair enough. (Though I have challenged him to a shootout, keyboard vs voice. I tried it myself yesterday, typing a tweet in 20 seconds speaking same tweet in 14 seconds.)
Although to be honest, the typed tweet appears instantly, the transcription of voice obviously lags a bit before it loads. But how often do you need real-time to a few seconds accuracy when you tweet?
(Awful pun alert:) Changing gear somewhat, consider too the millions of people in cars with hands-free phones, all of a sudden twittering becomes an option to them does it not?
(The M5 already tweets, tailbacks, accidents , breakdowns, but hands-free twitterers on the motorway turn services like this into, er, two-way 'traffic'.)
I can see it being used to provide running commentaries from sports event too, ala BBC Five Live, from a your local surf contest/mountain bike/school egg & spoon race for example.
I also suspect that spoken tweets might have a different 'energy' or feel than written ones.
So well done Twitterfone hope you get the recognition you deserve.
Incidentally, my only hitch was a login problem at 0700 yesterday. I contacted Twitterfone tech support, and got an almost immediate response and fix. Thank you Adrienne, great service.
(The problem incidentally was er, 'user error', not a Twitterfone problem, - I was doing something stupid at login. Nothing new there then.)
You can also link through to the Tweetfone audio page to hear the tweet too, should you so wish.
Yesterday I was trying it out in Centotre, I was just about to leave a voice tweet when the waitress, (Hello Sabrina!), came to take my order. As I dithered, ummed and ah'd, I decide to concentrate on my coffee order not the tweet, but clever clogs Twitterfone, managed to understand and transcribe and post my mumbling incompetence for posterity: