Derek Powazek:

Every community-​based site in the his­tory of the web has essen­tially been a stab at cre­at­ing a social net­work. Most of them fail as busi­nesses, with the rare excep­tion of small, lucky com­mu­ni­ties that become self-​sufficient but not exactly pros­per­ous. What if that’s just the way it is?