Protocol Buffers是Google公司开发的一种数据描述语言，类似于XML能够将结构化数据序列化，可用于数据存储、通信协议等方面。现阶段支持C++、JAVA、Python等三种编程语言。
Why not just use XML?
Protocol buffers have many advantages over XML for serializing structured data. Protocol buffers:
- are simpler
- are 3 to 10 times smaller
- are 20 to 100 times faster
- are less ambiguous
- generate data access classes that are easier to use programmatically
google大概是今天将其作为开源项目对外公布，说是后续还要开源的项目有不少都会用到Protocol Buffers。
给出官方文档的链接：http://code.google.com/intl/zh-CN/apis/protocolbuffers/docs/overview.html