UPDATE: The issue was resolved about 11 hours after the post was published. Like counts and comment counts are back. See TechCrunch’s post.
Today (3/25/13), Facebook appears to have made a change that has nuked all existing Facebook Like counts and Facebook Comments. I can verify that on this particular blog, my non-cached Like counts and my Comments are gone, even after checking Facebook’s Graph API directly. This can be verified on older blog posts, such as this one. It is also being tracked on Stack Overflow.
Note the lack of comments and Likes, on what was the article with the second-most pageviews on TC (and one I can testify that had hundreds of comments.) A quick glance at multiple blogs and other old posts confirms that Likes were reset. New posts have several likes, but all old posts have 0 likes.
I’m sure the lost Likes/Comments temporary, but this is an error of incredible magnitude, especially given on how many sites rely on Facebook’s data.
Because comments here may be broken, you can comment on the Hacker News thread.