FDA's sweeping definition of labeling includes what is said or represented, even by images, in a social media platform.
If the information can reach a consumer, FDA cares, even if you did not publish the information. Firm's need to watch for promotional trespassers. Websites, chat rooms, op-ed articles or even your own postings in social media can cause your product to be misbranded, i.e., illegal.
One big issue is how you patrol and control what someone else is saying about your product in a public forum. Once the off-label information is out there, what is scope your responsibility?