It’s a cardinal rule; journalists should not reveal their views on political or social issues because that puts their credibility at stake. Therefore I don’t think that this rule should be tampered with in the name of social media. 

A limit to what a journalist posts on social media is a good way to maintain a neutral viewpoint, thus maintaining professionalism. 

Given the fact that journalists have the power to influence or shape opinion, whatever they post on social media should be in check.  

For instance, that’s the very reason journalists are asked not to have any political affiliations because any kind of political support creates opportunities for favouritism in reporting and can create a perceived conflict of interest.

According to the National Public Radio (NPR) ethics handbook, the standards of impartiality also apply to social media. It states that journalists don’t express personal views on a political or other controversial issue that you could not write, air or post on NPR.org. These guidelines apply whether you are posting under their own name or if the online site allows pseudonyms, your identity would not be readily apparent. In reality, anything one posts online reflects on them and on NPR.

The handbook further indicates that simple participation in some online groups could be seen to indicate that you endorse their views. So a journalist of NPR needs to consider whether they can accomplish their purposes by just observing a group’s activity, rather than becoming a member. If they join, they should be clear that they have done so to seek information or story ideas. And if they "friend” or join a group representing one side of an issue, they should do so for groups representing other viewpoints.

Thousands of people follow journalists on social media sites like Facebook or Twitter because of the stories they publish or broadcast but not because they personally know the journalist. So if journalists get followers for the above mentioned reason, that’s a clear indication that whatever they post on these sites is influential. When someone has influence on people, they can shape opinions and be persuasive.

Journalists are supposed to put aside their opinions about social issues in pursuit of the truth. So if they try to post their opinion or comment about a story they are pursuing or comment about an issue, it instantly indicates the side they are on. 

A publication, Media Now: Understanding Media, Culture, and Technology by Joseph Straubhaar, Robert LaRosea and Lucinda Davenpor, states that for journalists to act independently they should avoid conflict of interest, real or perceived, and remain free of associations and activities that may compromise integrity or damage their credibility.