It seems to me that ZeroMQ is very good if you are creating a messaging network with load balancing, fanout, and fanin, however I don't think what most people are using HTTP services for matches to ZeroMQ full capabilities. That being said, it is very easy to get started with ZeroMQ. The whole idea of making everything messaging oriented seems to make sense especially if you think message passing is a good way to simplify complex systems that need high levels of concurrency. The issues with threading, forking, and contexts make some things tough with ZeroMQ, see: http://250bpm.com/blog:23. I stopped hacking on ZeroMQ when i was unable to trouble shoot some hard to reproduce crashes.