On the Mozilla website, there’s a page showing (apparently) live download statistics for Firefox: http://www.mozilla.com/en-US/firefox/stats/
How are they performing their request to get the live stats data? I can not see a constant connection in Firebug.
How is this working?
Looking at the country_report.json response in the Net tab of firebug, you can see something like this for each country:
So those graphs are not being updated every second in real time. Instead, they are plotting a recent history of requests, one point per second, and periodically requesting a new set of data to plot.
It seems they use something called SQLstream on their end to gather that data.