Facebook’s new commenting application is reportedly integrated into over 50,000 sites.
The others… I’m not too sure about.
And in the grand scheme of things 50,000 websites is not a huge number.
But what is huge is the way that Facebook comments is changing the game of commenting on sites.
No other commenting system can achieve what Facebook does in that it delivers massive syndication and referral traffic for sites that integrate it.
I would be interested, and will try to start compiling a list, of sites throughout the web that have integrated Facebook comments.