I was led to this by the following statement. "ØMQ doesn't know anything about the data you send except its size in bytes. That means you are responsible for formatting it safely so that applications can read it back. Doing this for objects and complex data types is a job for specialized libraries like Protocol Buffers."
Protocol Buffers are widely used at Google for storing and interchanging all kinds of structured information. Protocol Buffers serve as a basis for a custom remote procedure call (RPC) system that is used for nearly all inter-machine communication at Google.
Protocol buffers are Google's language-neutral, platform-neutral, extensible mechanism for serializing structured data – think XML, but smaller, faster, and simpler. You define how you want your data to be structured once, then you can use special generated source code to easily write and read your structured data to and from a variety of data streams and using a variety of languages – Java, C++, or Python.
A friend of mine mentioned why would I use this versus something like java serialization. Here are a couple good reasons to use protocol buffers versus java serialization.