What is Social Media?

I asked the same question about 2 years back where I knew nothing about it. But today, it's something I love doing. For me, sharing is caring. But today, I believe there are many people out there who are still very puzzle what Social Media is.
As I was browsing for some article, I came across this youtube, "Social Media In Plain English". I spend a few minutes checking it out and I personally think it is simple for people to understand. I am sharing it here so you all can learn a thing or two.