On April 12th, Microsoft announced that:
"the Bing Search API will transition to...the Windows Azure Marketplace," they later added that the service will "move to a monthly subscription model."
So what does this mean for developers?
First of all, Microsoft did not specify when the change would occur; they only say "the transition will begin in several weeks and will take a few months to complete." Meanwhile, the existing Bing Search API 2.0 is still available, free of charge, and the new Bing Search API on Windows Azure Marketplace will also be free during the transition period. So don't worry about paying for it yet.
However, the new Bing Search API will take advantage of the Azure "platform as service" infrastructure. This means developers will need to migrate current apps to incorporate "a new API end point, moderate changes to the request and response schemas, and a new security requirement to authenticate your application key," according to the Bing Developer Blog. The changes are non-trivial, but mostly straightforward, and the documentation is already online.
Charging for a service which used to be free is sure to be controversial, but Microsoft promises "fresher results, improved relevancy, and more opportunities to monetize...usage of the Search API." And, to be fair, the proposed pricing--"$40 (USD) per month for up to 20,000 queries"--means you get five queries for a penny. Microsoft also specifies that high-volume users (more than 3 million queries a month) will transition to the new API through a separate process, details of which have not been announced yet.
Is this bad news for some developers? Possibly. But the promise of Azure being a "one stop shop" for APIs is compelling, and if Microsoft chooses to separate Bing Search data into "premium" and "free" offerings, tinkerers and hobbyists may still be able to experiment before opening their wallets.
(Hat tip: The Next Web)