Even if Bing isn't all that popular with programmers, I'm pretty sure it would come in higher than Yahoo did in that list. As far as I know, Bing has actually had moderate success in getting some marketshare from Google, though nothing outstanding, and while programmers are not representative of wider demographics, you will probably see at least some of them using Bing.
My understanding of Bing's "success" is that much of it has been in contracted search -- setting up Bing as the default search service for specific sites and/or online services, or something like that. No, I don't know specifics, but it's similar to earlier games MSFT played with IIS numbers -- setting up IIS as the default "parking" domain for some large domain registrars.
