Google is totally a no on this count. Their generally-available programs are all for people entering search terms into Google's own widgets and specifically exclude software sources. I asked around at I/O and the answer was basically a shrug and suggestion to "get big and call biz dev".

I fully understand why, of course — they have lots of tools and expertise for verifying the authenticity of web-based queries, but software has to monitored in a different and likely less scalable (maybe even human-driven?) way.

And Google hardly needs to pursue desktop apps' small (and, to be fair, traditionally risky) traffic source, so in turn they haven't developed the technology to make that scale better.

I still love Google search though, so I wish I could use them. Instead I have to choose between monetizing what is clearly very valuable search traffic and giving users a search experience I think is outstanding. It's really frustrating.

If anyone has any ideas how I can cut this Gordian knot, feel free to get in touch via my profile info.

Perhaps you've never had the misfortune of using one. Google's CSE is atrocious. It looks terrible and has poor functionality.