By some counts, Twitter now has 500 million users -- but is that enough of a critical mass to ensure that the microblogging service doesn't fizzle out? Other analyses suggest that the site's active user base is substantially smaller, and that Twitter isn't out of the woods yet. "It's not so hard to imagine the 200 million or so monthly active users finding another club to play in," Rebecca Greenfield writes.

Full Story:
The Wire

Related Summaries