A primary design goal of the Open Graph protocol — which enables any Web page to become a rich object in the social graph — has been to make it simple for developers to integrate it into their Web pages. But, as with any coding, syntax errors can and do occur. To help you debug your URLs, we've released the Facebook URL Linter.
At this time, the linter returns warnings for any issues it encounters. In the near future, the linter will start returning errors. These errors will cause the Like button to stop working on your page.
We also plan to add Open Graph protocol type metadata suggestions, and a lot of helpful messaging. If you have any feedback, we'd love to hear it on the Developer Forum. Make sure to put linter somewhere in the post, to help us find it.
This week we've also added Open Graph protocol markup to every public Page on Facebook. This makes it easy for anyone to know that Starbucks is a company, the White House is part of the government, and Weird Al is my favorite musician.
Paul is a lint-free, white and nerdy hacker on the Platform team.
Note: In case you were wondering, the Facebook URL Linter's name hails from the original lint UNIX program.