There's alot more that can be done with the technology. We wanted to start with a few core partners and drive the quality and relevancy up as we go - so, can we? Sure. It's a matter continuously improving the service
And, agreed, MSR does some cool stuff :)
I just tried putting "site:github.com How to compute MD5, C++" into Google, and it seems to work.
As you mention, GitHub doesn't fare that well: "We couldn't find any repositories matching 'How to compute MD5, C++'"
Have you considered perhaps including more data sources ? I'd imagine for example a public code repository like Github or Codeplex will extend the range of possible "How Do I" questions that can be answered.
On an unrelated note, I have almost always been disappointed by the search-quality of Github. I know they have a lot of public code but they don't do a good job of surfacing relevant code results. Imagine for example, how cool it will be being able to type into Github, "How to compute MD5, C++" and seeing the relevant code.
Actually, thinking about it, there is nothing preventing Microsoft Research from taking this tech, and turning it into a natural language web code search service. Now that would be awesome !