From the Guardian:
Experts are warning internet users to be more careful with their private information after secret code from the popular social-networking site Facebook was published on the internet.
This is the first time that some of the site's secret operational code has been made public. Although it does not allow hackers to access private information directly, it could help criminals close in on personal data, according to one expert.
Nik Cubrilovic, of Techcrunch.com, said: "This leak is not good news for Facebook, as it raises the question of how secure a user's private data really is. Facebook has become such a success and has such a high profile that it has become a magnet for attacks against its systems."