[zerokyuu]

I don't know if GMail itself is "research", but I'm sure there is definitely a lot of systems research going on behind the scenes. I don't know that they use it for GMail, but the Google File System paper was interesting. Allowing their users (millions?) to quickly search their email (tens to hundreds of thousands?) must have some interesting networking/distributed systems research questions.

That said, some more publications/insight on those systems would be nice to see.