From the perspective of a future historianIn history, we try to find what happened in the past by using sources, either written ones or archaeological sources. It is quite unfortunate that throughout human history, the written sources, whether it is books or inscriptions or anything else that you pick up, have mostly been composed by a small minority of literate elites. Often, therefore, the biases of the elites are reflected. Therefore, a historian studying, say, the Gupta period will easily come to know the territories that Samudragupta conquered using sources like the Prayag Prashasti, but to find out what the ordinary people thought of Samudragupta, or what living standards they enjoyed back then, would be quite a formidable challenge. This is of course not to say that such questions are unanswerable. For example, folktales and folk songs give us a gateway into the attitudes of the common people, as well as certain Jataka stories. But on the whole, there is a dearth of material composed by the common people themselves.
Now think from the perspective of a historian belonging to a future period, say, 2500 CE (I hope humanity survives till then) who is trying to study the first half of the twenty-first century. Due to mass literacy and platforms like social media websites, there will be an ample amount of material for him to depend upon. The actual experiences of the people, their way of living, their opinions about the government, their food habits, etc will all be available for the historian who will have an enormous amount of data at his disposal (Hopefully, technology will have made major leaps by then and he won't have to manually sift through all of our posts).
That is the power of social media, one which is so often neglected. As messy as it might be, it has allowed the common people to voice their opinions and to leave their records for posterity, a power which they didn't have in the millenniums gone by.