[geophertz]

Would you mind sharing who those independent fact checkers are?

[danpalmer]

I think it's a joke, this is the text that Facebook puts at the bottom of some false information.

As with all jokes though, I think there's an element of truth to it. May not be independent fact checkers, but discussion in this thread covers the iMessage comparison and I wouldn't say it's as clear cut as Zuckerberg would like to make out.

[mikro2nd]

Hmmm... Except for the fact that people who don't use Facebook are never going to get the joke...

[danpalmer]

I don't use Facebook, but I know enough about their half attempt at fact checking to get the reference.