Mass and social media communications are rarely effective at resolving conflicts because they try to address the problem at the system level, but the problem is at the level of individual interactions.
We've all seen it. Those painfully earnest ads, tweets, and posts by project proponents who are convinced that, gosh darn it, if people just understood "the facts" about their project they would climb on board and stop opposing it. Look at how many jobs we'll create! Look at how good we are at cleaning up our mess after the fact! Look how important this is to our economy! Look how many females/under-represented groups our industry employs! Or my favourite one: Look at how much worse the other proponents/industries/groups are!
Mass and social media communications are important but they usually don't work to alleviate direct conflicts, because not only do they miss the actual source of the conflict, they usually just end up reinforcing it. Here's a helpful way to think about it.
Scientists who study complex human conflicts from a systems (i.e. big picture) perspective often liken them to natural phenomena, like a flock of starling birds who fly in formation in an ever-changing, dynamic pattern that you can never hope to predict. The flock seems to be an entity unto itself, beyond the individual birds themselves. The birds are just focusing on the others in their immediate perimeter, not on what the flock is doing as a whole. Similarly, human conflicts can be thought of as the result of patterns of interaction that also take on a life of their own, very much like a flock of starlings. In the case of difficult conflicts those patterns are stable, but also destructive, like a group of starlings that refuses to engage with the others and just plows through the whole flock.
Intuitively, this makes sense. Longstanding conflicts that have a heavy emotional or value-based component can be destructive, and enduring, despite the fact that they're counterproductive to most everyone involved. This is because natural systems like human conflicts take on lives of their own, where the conflict itself is often much larger than the individuals involved intended it to be. Some call it herd mentality, swarming, or self-organization, but whatever you call it, the reality is that difficult conflicts are often much bigger than what the people involved intended.
What is not intuitive about this approach is the idea that you cannot expect to change a conflict by focusing your effort at the big picture level; any more than you can hope to catch a flock of starlings with a net. You need to focus your effort on the changing the patterns of interaction that created the conflict in the first place. In most conflicts, that means you need to find the parties who are actually diametrically opposed to each other (as opposed to those who are merely influencers), and shake up their existing patterns of interactive at the individual level.
Mass and social media communications are rarely effective at resolving conflicts because they try to address the problem at the system level, but the problem is at the level of individual interactions. For example, if an environmentalist has decided that corporate energy extractors are focused on profits more than protection, mass communications about jobs and economic impact are only going to reinforce that - not make it go away. Similarly, if an engineer thinks that eco-warriors don't understand basic thermodynamics and the efficiency of close-to-the-source combustion, communicating the virtues of electric cars that are actually fuelled by coal-fired electricity is not going to be persuasive either.
Mass and social media communication have their place, but they are blunt instruments. Don't bring a sledgehammer when you need a scalpel. If patterns of interaction are the source of difficult conflicts, then more nuanced, direct approaches (engagement, mediation, co-creation of strategy, etc.) are called for in cases of direct conflict. Don't tweet - meet.
Go deeper:
Coleman, P. T., Nowak, A., Bui‐Wrzosinska, L., Bartoli, A., Liebovitch, L. S., Musallam, N., & Kugler, K. G. (2011). The Five Percent: Finding Solutions to Seemingly Impossible Conflicts (1st ed.). New York City: PublicAffairs.
Vallacher, R. R., Coleman, P. T., Nowak, A., & Bui-Wrzosinska, L. (2010). Rethinking intractable conflict: The perspective of dynamical systems. The American Psychologist, 65(4), 262–78. http://doi.org/10.1037/a0019290
Musallam, N., Coleman, P. T., & Nowak, A. (2010). Understanding the spread of malignant conflict: A dynamical systems perspective. Peace and Conflict: Journal of Peace Psychology, 16(2), 127–151. http://doi.org/10.1080/10781911003691591