[foamflower]

IANAL either, but two things stand out. First, breach of contract is not a criminal wrong, only a civil one. Second, it would be a big stretch to say that the relationship between users and Facebook (or any nominally free service) is a contract, as valid contracts must follow certain requirements like consideration or a meeting of the minds. This is partly why things like the Computer Fraud and Abuse Act that e.g. Aaron Swartz was being prosecuted under (persecuted, IMHO) can be so alarming: things like terms of service normally wouldn't even stand up as a contract, but under CFAA, they can give rise to criminal charges.

I have no idea what charges the Eastern District of NY might be seeking pursuant to these data deals, but maybe something like mail/wire fraud or honest services fraud? Again IANAL, but those are fairly broad and the government could make the case that Facebook fraudulently breached its duties to its users.

[lithos]

Read the article. This discusses violations of an agreement between Facebook and the FTC. Not an agreement or ToS between users and Facebook.

[foamflower]

Did you read OP? In context, the idea is clearly that Facebook violated some sort of contract with its users.