It was only last August that Chartbeat passed one million concurrent users tracked across all the sites that use the realtime analytics dashboard. It took 16 months from launch to get there. Now, a mere five months later, Chartbeat has broken through the 2-million user milepost.
Chartbeat is like Google Analytics, but in realtime. It lest you see exactly how many visitors are on any page on your Website at any given time, where they came from, and how your realtime traffic compares to the norm. So you can see spikes right when they are occurring. I use it religiously to track how posts are doing on TechCrunch every day. And more and more sites are getting religion, it seems, or traffic is growing for the already-converted. The 2-million user number is concurrent users across all sites that use Chartbeat, and that is an average number at any one instant.
It is certainly a popular service. In fact, it is up for a Crunchies award this year for Best Interent application. You can vote for it here (along with other nominees).