And Twitter's numbers are extraordinarily misleading, because so many of their accounts are fake, and so many people just sign up but never really use the service.
I signed up for Twitter around January and frankly speaking, couldn't find my way around. I've heard people speak of retweets, DMs, hash tags and variety of other terminology and didn't seem to find an explanation of what they all meant or did after I signed up. In fact, I really didn't know what to do and just logged off and didn't bother with Twitter again until a couple of months later when I thought of trying to find and meet up with other coders in my city and thought perhaps Twitter might be a way useful way to accomplish that task.
I found if I search for #[MyCity], there were a bunch of tweets with #[MyCity] so made a tweet along the lines of "Any coders in #[MyCity]? Let's meet."
8 hours later, I search #[MyCity] and my tweet wasn't even in the list. I asked on /r/Twitter and was told tweets from new accounts don't make it in the search results as to suppress spam. As a guy who doesn't know anyone on Twitter and who nobody knows on Twitter I feel like the service simply is unusable. The impression I'm left with is that Twitter is only useful for "brands". As a regular schmo who isn't a "brand", I don't see the point of using Twitter and thus my account is inactive.
To take one simple example, half of Bieber's followers are fake. I'd be willing to bet that between 1/3 and 1/2 of all followers on public accounts are fake.
http://www.bbc.co.uk/newsbeat/22104058
Then on top of this, I'd like to see how many Twitter users post a few Tweets and then give up. It's not hard to calculate that data just by sampling a large number of users from the API. I'd argue it's an extreme portion of the supposedly active user base.
Mostly Twitter is shallow (as in limited use and interaction) consumption platform, with relatively few highly active producers.