Yahoo! Search web services

Yahoo! introduced REST APIs for web, image, local, news, and video search as well as Overture listings.

Yahoo! uses an application ID and limits requests by IP address. Service limits are set at 5000 requests per 24-hour period starting from the first time Yahoo! receives a call from the IP. This configuration allows for a developer to distribute his or her application without worrying about a user setting up their own API key. There could be issues on shared hosting setups where there are hundreds or thousands of domains sharing one IP address.

You may not use the Yahoo! APIs for commercial purposes. Yahoo! asks developers to use a special click URL they can track the use of their APIs.

True URL
Click URL*-http%3A//

Yahoo! does say please, but I see no reason for a developer to include the click URL in his or her application. Translating some parameters from the click URL above I am transmitting back to Yahoo! information that the user searched for “niall kennedy” (K) using the Yahoo! Web Services experience (XP) version 2 (v), the time the search took place (EXP) and more data not easily discerned.

The API response includes in its HTTP headers a P3P policy and an attempt to set a cookie.