The ground is still fresh on defining and enforcing the legal consequences of posting or hosting contentious material on social media. Litigious parties haven't pursued many cases into the courts yet.

Poynter's Mallary Jean Tenore contributes an overview for U.S. journalists that bears reading by others, too. In it she cites the boundaries emerging in the courts on how libel can and can't be pursued.

While it is true that a libel is a libel wherever it is published, there are some protections worth noting: Third-party content can be hosted or reTweeted seemingly without consequence (although any libellous material you insert will have an impact on you).

Another variation: A news organization employee's Tweets might not be problematic for the organization if they are not work-related (the employee, of course, would have a problem).