- Facebook users spend ≥ 8B minutes/day collectively on Facebook (that's more than 15k years/day); that makes Facebook the No. 1 site in US in terms "time spent per day"
- 5B API calls to Facebook API per day sent by approx. 15k client applications
- More than 300M active users
- Generating 25T of logs per day
- Over 2B photos are uploaded per month; currently there are 20B photos in total for which Facebook stores 4 different resolutions
- Serving 1.2M photos per second (this was mentioned in the abstract of the talk)
Those seem to be the official numbers that I've seen also mentioned at Facebook's Engineering Roadshows. Dare Obasanjo's notes from the Engineering Roadshow in Seattle highlight a couple of other interesting numbers:
- The average number of friends per registered Facebook user is 130
- The page with the most fans is Barak Obama's page with 6.8M fans
- The fastest growing demographic is user aged 35 and older
- There are more than 350k Facebook applications
- The impressive image storage and serving statistics mentioned above make Facebook the No. 1 photo site on the web
I'm also on Facebook, but given that I have less than 130 Facebook friends and I'm also visiting the site at most once a week, I'm probably far from being an average Facebook user.