Yes, SPDY is a cross-platform protocol. This submission is a Ruby implementation of a SPDY server for Rack applications like Ruby on Rails. The news.ycombinator.com server is written in the arc language. SPDY is awesome.

Ok. It's my fault for not being clear in my original message. I wasn't talking about the linked SPDY implementation but about SPDY in general. Sorry, I should have marked it as OT.

All good - we are all here to share knowledge :-)