Visitors to such sites as CNN, The Washington Post, BuzzFeed, the Gawker network (including Gizmodo), and NBC News were instantly transferred to a Facebook error page upon loading the intended site.
Users not logged into Facebook did not get the error, which led people to conclude, correctly, that the problem was with the Facebook Connect service, which governs "likes," "comments" and other Web-based features of the social network.
For a short period of time, there was a bug that redirected people from third party sites with Facebook Login to Facebook.com.
For other sites it was longer; ReadWriteWeb said the bug lasted about an hour, from 4 to 5 p.m. PT.
Those on Twitter (and Facebook, of course) jammed those sites nearly instantaneously with comments on how it was a little disturbing that Facebook could essentially hijack a large part of the Internet — even if it was unintentional.
If the error had not been fixed by Facebook in a timely manner, the affected sites would likely have be able to intervene by disabling the widgets themselves.