More on the Mozilla Raindrop community can be found here. The @raindrop account at Twitter doesn't however seem currently active - or indeed searchable.
As always, it is my hope that we can find synergies that allow all these technologies to work together and support each other - that, in fact, people can impose their own virtualised socialising behaviours on those companies which would - otherwise - have us become consumer robots.
I am a great believer in the resilience of constructive human behaviours.
We are all social beings in search of like-minded communities.
Let it long remain so.