MS could argue that by posting information on twitter he was a publisher, and therefore he was breaching an embargo against publishing info (an NDA is a different matter, since he didn't sign one).
lol, what? Embargo is obligation from NDA.
How do you think this works, unless you sign agreement, Microsoft cant enforce anything against you. Only thing enforceable without you signing anything is the law.
This is all about consumer rights... Microsoft does not think that consumer has any rights.