Microsoft will charge $40/mo for 20K queries for access to the Bing Search API
thenextweb.com
thenextweb.com
[1] http://help.duckduckgo.com/customer/portal/articles/216399-s...
I am confident, however, the folks at DDG planned for events like this.
On a different note, it seems both Google and Microsoft are in a battle to first commoditize the other's core product and then start charging. Google's getting more aggressive with charging for Apps. And now Microsoft with the index.
A side project of mine is a search engine for coders (www.gigglebang.com) which I'll now have to take down or put ads on.