One of my brothers lives in a very rural area on Maryland's Eastern Shore. (That's the part of our state that lies between the Chesapeake Bay and the Atlantic Ocean). He doesn't own a computer, and transacts business the same way we all did 40 years ago. He writes checks to pay his bills, watches the television to get his news, etc. Does it work? Yes, but in this day and age it ain't the most efficient way to stay connected.
I like the immediacy and efficiency of Facebook. And it's great for communicating as a community. I belong to several fire service-related groups on FB, and just recently got some detailed information from a source there about my great-grandfather, who was also a Baltimore firefighter. In 2013 my high school classmates organized a joint 60th birthday party/reunion through Facebook. And just yesterday, a little girl who was missing here in Maryland was located in North Carolina through an Amber Alert posted on Facebook.
Yeah, it can be redundant, but it also offers advantages no other internet entity does.