I agree with Sergio. Since Hashnode aims to be a conversational community platform to me it's basically Facebook for developers without the annoying food and cat pictures.
It goes even further, at least sometimes, I think my input adds some value :). It's less voyeuristic and more topic related.
I mainly have facebook so certain friends can create birthday-events but hashnode I enjoy. At least till now :P
So topic related - developer - social network / aggregator would be my rough description.