I disagree with parts of this - Google does release some rather high-quality source code (LevelDB, Protocol Buffers, Chrome/V8), and also provides some well-done research papers.

The entire concept of MapReduce wouldn't exist without Google. And that's inspired a whole host of products. In the same vein, I don't find it unusual that they're NOT sharing the code for MapReduce et al., in that it's proprietary technology. I don't expect Amazon to share the source code behind AWS, and I don't expect Google to share the source code for MapReduce.