But the part I don't get is Why? Why should I proxy the third parties through Cloudflare to obtain multiplexing? They already are "multiplexed" by virtue of being on a separate domain. I already have great parallelism for those resources.
TCP connections take a lot of time to setup, and go through a ramp phase (slow start), especially on mobile where RTT is 200-1000ms. The theory is that by multiplexing multiple requests over the same connection, you'll get faster overall load time.
You can think of domain sharding as a workaround for the fact that HTTP does not allow true multiplexing. With SPDY, we can avoid that complexity and reuse the same connection.
Right but if I've goth links to third parties already, proxying them through Cloudfare does not reduce complexity, and would not reduce that connection setup time, since the connections already get set up in parallel. It might even add latency. I can see how spdy reduces complexity by permitting me not to have to deploy static links to different domains. I just don't see an advantage in changing links that originate on third parties already, to proxy through cf and multiplex.
