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 !
As you mention, GitHub doesn't fare that well: "We couldn't find any repositories matching 'How to compute MD5, C++'"
And, agreed, MSR does some cool stuff :)
PTVS: http://pytools.codeplex.com NTVS: http://nodejstools.codeplex.com
disclaimer: msft employee.
Now i have to [ctrl] + [space], click on how do i, then search. Is there an easier keyboard only way like your web example?