Under US law at what point does information become "public knowledge"? (Internationally)

Example

(US) Marketing company A sends out information to (US) Shop B about a future product classified as a "trade secret". Information may include a disclaimer stating this information is not to be made public until a set date, it may not.

Shop B then posts this information on its Web Site excluding any disclaimers potentially sent with this information.

(International) Forum Blogger C notices this information while browsing Shop B's Website and chooses to post this information on his forum. Completely unaware of whether this information falls under Trade Secrets agreement of any kind due to the information they see being on a public site.

While I'm aware Shop B has broken the trade secrets agreement (assuming they're aware this information is not to be made public before said date), how does this affect Blogger C? While the information obviously should not have got out at this point, is it classified as public information, due to being taken from a public site?

If certain states/countries are needed, happy to provide them, though unless required, and make a difference to the result, I'd rather keep them off of the forum.

Thank you for any comments made, I'm unsure exactly at what point (Under US law) this information would be considered public knowledge.