NPR updated its social media guidelines as part of its new ethics guide.
The section begins with this admonition:
The internet and the social media communities it encompasses can be incredible resources. They offer both a remarkably robust amount of historical material and an incredible amount of “real-time” reporting from people at the scenes of breaking news events. But they also present new and unfamiliar challenges, and they tend to amplify the effects of any ethical misjudgments you might make. So tread carefully. Conduct yourself online just as you would in any other public circumstances as an NPR journalist. Treat those you encounter online with fairness, honesty and respect, just as you would offline. Verify information before passing it along. Be honest about your intent when reporting. Avoid actions that might discredit your professional impartiality. And always remember, you represent NPR.