Dan Frommer in Business Insider | Feb. 22, 2010
A nice milestone for Twitter: It has now passed 50 million tweets per day, up from about 2.5 million per day at the beginning of last year.
This is one of Twitter’s most important metrics, so it’s a good thing that it’s still growing rapidly. Because Twitter is a distributed service all over the Web, on desktop clients, mobile apps, etc., “unique visitors” to Twitter.com has always been a somewhat flawed growth metric. (Though it’s obviously important for Twitter’s user base to continue growing, too.)
Here’s Twitter’s blog post on the achievement, posted by analytics staffer Kevin Weil: