I have reconnected with people whom I bowled with (and against) 30+ years ago. I've found old friends from the neighborhood where I grew up. Deb stumbled across her best high school friend, they had lost touch three decades ago but they went to the last Hilton Suited BJT together. And it is an excellent promotional vehicle for businesses, either web-based or brick-and-mortar.
It's not everyone's cup of tea, for sure, but for many folks it's a fantastic way to keep up with friends/family whom they might ordinarily miss for years.