Are there figures for the number of webusers that have facebook?

[smithaa02]

Considering using facebook for some authentication and am trying to find stats as what percentage of web visitors would actually be able to log into facebook (specifically for America).

Are there general stats out there for something like this? Did some searching and found overall facebook users, but that doesn't tell me what percent of all web visits are from users with facebook.

[anallawalla]

800M users worldwide. 75% outside the US:

[facebook.com...]

I don't know how many of them are bot-generated accounts.

[TheWebSurgery]

Yep! i think 10% of it would be Spammy accounts..

Though it is really intersting to know

'More than 800 million active users
More than 50% of our active users log on to Facebook in any given day
Average user has 130 friends'

[ember]

I've heard that 200 million are in the US alone.

[ProSEOServices]

50% of them are active actually