What is it all about?
Protocol Buffers (a.k.a., protobuf) are Google's language-neutral, platform-neutral, extensible mechanism for serializing structured data.
* Protocol buffers are a flexible, efficient, automated mechanism for serializing structured data – think XML, but smaller, faster, and simpler. * 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. * You can even update your data structure without breaking deployed programs that are compiled against the "old" format.