Twitter's burn rate: Our search gets closer

It's impossible to tell if the new US$250 million valuation of Twitter makes it a bargain buy, or a money-eating monster. That's because no one has ever published a serious dollar estimate of how much Twitter spends per month sending out (the short text updates typed by members) for free as SMS messages. Twitter the company pays for those itself, so a fast-growing audience means a fast-growing phone bill.

Monday I we need: The number of SMS tweets per month -- preferably for several months, so we can extrapolate growth -- and the price per message Twitter has negotiated with wireless carriers. Twitter co-founder Biz Stone politely emailed to me to say that sorry, no, they won't tell us those numbers.

My fellow biz-bloggers, though, had plenty to say. Valleywag editor and Twitter power user emailed a snappy 182-word rebuttal:

There is a pretty fundamental mistake here, which is that it assumes all Twitter users use text messaging as their primary interface to send and receive messages. They don't. I don't think most do. I used Twitter on my cell phone for about a week before concluding it was driving me mad.

It's pretty easy to see how many messages are sent via text message; look for tweets which say "sent from txt." Much harder to divine: How many are received via text message. But it's safe to assume that someone who is using, say, Twitteriffic to post messages is also using it to read messages. No cost to Twitter. And many people may send messages to Twitter with their phones, but read friends' messages online. (That's how I do it.) Small cost to Twitter.