This exists already, but you have to do some work to find it. LiveJournal used to be particularly good at making friends with random strangers; I'm still in touch with some that I made a decade ago in the Harry Potter fandom, even though I've never met them in person. Also, all the niche forums on the Internet - whether your interest is Game of Thrones, Starcraft, startups, JQuery, Apple products, Linux, gymnastics, food, Harry Potter, Star Trek, or NaNoWriMo, there are communities out there for you. You just have to do some Googling and link-following to find them.