Actually, I think there are things you could call a 'social layer' that can be added to any product, for example:<p>1) Identity. Moving each product from having a silo'ed identity profile to having a centralized social profile.<p>2) Contacts. Many many products need to know not just who you are, but who you will be collaborating with. From sharing, to basic ACL settings on documents. For the consumer side, Social contacts replaces the previous layer that was used: Corporate LDAP servers or Mail servers (Notes/Exchange/ACAP/etc)<p>3) Sharing. Pretty much every app features some form of collaboration, even if it just means sending a link to someone.<p>4) Activity Log. Moreover, it is useful for many apps to keep a history of recent actions you've taken, either for the purpose of rolling them back, or for allowing you to search and find knowledge, either about what you did, or what a collaborator did.<p>dcurtis is basically repeating Zuckerberg's claim that social is something you can't add later, and I think this is hogwash. Sure, you certainly have to re-design the API. But that doesn't mean you have to invent a whole new product.<p>YouTube for example, doesn't have to throw away their entire product and start from scratch vs a product that may have been built from scratch for sharing videos on a social network.<p>I believe far far too much credit is being given to all kinds of hand wavy arguments about designing for social, or 'social dna', and not enough given to simple market timing, niche targeting, and network effects with respect to Facebook.<p>At this point, Facebook could produce really terrible product addons, they'd still continue to gain users. And competitors really can't differentiate themselves enough to siphon off users, because the marginal gain in utility isn't worth the switching costs.<p>Social networking, if it is as important as everyone says, is a commodity. Facebook's wall-garden has a substantial network effect of making it costly to choose other networks. If Facebook had been invented as a federated, distributed, open social network in the beginning, then, and only then, could you make all kinds of arguments about their user base being related to mythical 'social dna' or superior design ethos.<p>It's like looking at Microsoft Windows user base in the 90s, and saying it indicates that Apple "doesn't have desktop DNA" design chops, because clearly, all those users use Windows purely based on design decisions Microsoft made.