We don't want to beat a dead horse regarding how hot Twitter is, but the data from an independent tweet-counting service is so compelling we just had to share. According to GigaTweet, the number of tweets passed the five billion mark earlier this week. We're not sure how long the service has been going or how its dynamic counter measures tweets, but Mashable's Barb Dybwad notes that the counter stood at nearly 1.6 billion tweets on April 23, meaning in six months Twitter has apparently experienced more than 200% growth in the number of tweets.

Of course, when it comes to hot Internet services with a social twist, exponential growth has a way of leveling out as the population of potential users is tapped out or people move on to new and cooler things -- just ask the founders of MySpace. Another question: How many users does Twitter have? This guest post on TechCrunch by the CEO of RJMetrics applied some statistical analysis to the question, and concluded that Twitter had just over 50 million "live Twitter accounts" on September 1, and was gaining 8 million new users per month -- but it's a level that RJMetrics said was "no longer accelerating."

Lastly, we're still waiting to hear how @Biz, @Ev, @Jack and the rest of the Twitter gang hope to make money from Twitter. "Free" is great, but it doesn't pay for a batch of new servers that are required to scale Twitter and serve the next 5 billion tweets.

Sources and research: GigaTweet, Mashable, TechCrunch

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