Here, I read a long time ago it counts the number of browser windows open. I don't know if that is still the same as Renderosity has changed since then. I counted the number of people online at RDNA and it matched the total displayed. Normally for an online script they take 300 seconds which is 5 minutes. If the time frame is too big there is no point in it. There could be deviations but the figures are too vast for it to mean much.