the sane strategy would appear to be to have some redundancy in your frending behavior. when you add someone to your network via these social networks, add them in multiple places. then if any of those goes casters up (or you abandon it for some other reason) it’s not a total loss.

this is also the argument for loosely coupled systems that are a pain to manage but that are robust in times of failure – why you have a phone book with similar but not exactly the same data in 3 places that’s always a little out of date but always there even if you’re offline and the power goes out.

if the community is strong enough it will outlast whatever temporary software scaffolding holds it together.