Could you explain a bit more how it works because, if a see the big picture, I fail to see how it could be useful outside Twitter's stack. I mean it seems to heavily rely on Finagle, right ? Please correct and explain if I'm wrong.
If you wanted to record and forward traces inside your own services, this is relatively straightforward (though not super trivial) to do. There are other implementations beyond the Finagle one in development by the community - I would suggest hopping on to the zipkin-users Google Group.