Reinhardt: Social media like Facebook, Twitter, and a number of others are of course 
“community-oriented,” but that doesn’t make them vessels for actual communities. Think of it like this: a small town newspaper is “community-oriented,” but the newspaper itself isn’t a community, it’s just one very, very thin slice of it. An actual community is a social institution of much, much greater complexity. It’s made up of hundreds, or even a few thousand people who live among each other and engage each other on wide range of levels. Community members interact through family, work, religion, education, politics, leisure, and commercial activities just to name a few.
Here’s another way to think about it. I wrote a book. I’ll be using Facebook to promote that 
book. And through that, Facebook has a very real connection to the book. But at the end of the day, it’s a very minor connection, and Facebook is not the book. The book is the book. Likewise, an actual community could use Facebook, or another online social media outlet as a tool for communication, and in that way Facebook would have a very real but, all things considered, very minor connection to the community. But that doesn’t mean we should confuse Facebook with the actual community it might be connected to.
My argument is that in America there are no more actual communities, and I end up defining social media like Facebook as surrogate communities: things that people now use to recreate in some ways the connectedness of an actual community, a replacement to fill in for missing communities. But that doesn’t make it an actual community. When used in that way, it’s a pale imitation.