IanKelley - 9:37 am on Jun 14, 2011 (gmt 0)
Where do Inside Facebook's numbers actually come from? The nature of Facebook would seem to make it impossible for a third party metrics service to do anything but guess.
Don't get me wrong I can think of a lot of ways that you could educate your guess (scraping public profiles, maintaining multiple large networks of FB friends/likes, using other 3rd party traffic numbers, running ad campaigns in order to grab demographic data, maintaining popular apps to mine user's data, etc...).
But ultimately it's still a guess, and one they have an interest in exaggerating for PR purposes.