I will start by saying with absolutely no reservations that social media - or more specifically the democratized ability for any individual to communicate to the masses at will - has been the single most positive invention in the entirety of human history; that future history will show that it had the widest impact on the nature of human society than any technology that proceeded it; and that it won't be surpassed in it's impact until the invention of dirt-cheap matter transmutation technologies or affordable faster-than-light transportation (whichever comes first).Honestly, there's a whole conversation that shouldn't take place in this thread about whether or not the improvement in communications via social media has been a net positive or negative for our society.
It has already completely altered the distribution patterns of all forms of art, from music to video to photography to the written word and etc. No longer can only a small handful of artists make a living on their art based on the access granted to them by the publishing empires to the customers they need to sell their art to, now the artists have public channels of communications to individual consumers that can purchase their artings directly. At the same time that there's been a slow reduction in the number of multi-millionaire artists that society is supporting there's been a sudden and massive explosion in the number of artists that can now make a basic living off of their art that never could before. That's huge, and it will make a big impact on where our economy goes from here as we transition away from human labor as a primary resource in every industry from manufacturing and transportation to customer service and middle management. I can't predict exactly what that means any more than a farmer in the early 18th century could have predicted the manufacturing boom of the 1940s, but I can see that massive change is coming and social media will play a pivotal role.
More importantly are the political ramifications. It is getting increasingly difficult for the powerful few to keep the masses in check through threat of force and ignorance of what is going on in the world in countries like Egypt, Iran, and on and on. The cowed and ill-informed masses are no longer likely to stay that way thanks primarily to social media. This doesn't currently apply so much to first-world countries where the masses can be held in check by their creature comforts and prolific entertainments, but if those comforts and entertainments are interrupted then revolution is not nearly so far away as it used to be. All it takes is for a certain large enough segment of the population to rally on social media to start a ball rolling that dictators and tyrants can no longer stop. It is becoming the driving force of democracy and making the first amendment more immediate and useful than the second in such matters.
I could go on all day. In my opinion all of these positives, both potential and already realized, far outweigh any negatives that come along with it in the form of trolls and massive amounts of meaningless noise. Social media has given the people a voice. Sure, sometimes they use that voice to call each other dicks or show everyone their lunch, but the fact that they have that voice available when it is needed for other purposes is the best thing that has ever happened for the future of civilization so far.