More on MSN Search API's
This post compares the query limits of free search APIs from different providers. It highlights that MSN Search API reportedly allows up to 10,000 queries per day, but whether that limit is per API or in total is still unclear. The post also notes that Google's Search API allows 1,000 queries per day, Yahoo's APIs allow 5,000 queries per API per day, and Amazon's allows a generous 86,400 queries per day (calculated as 1 query per second). More investigation is needed to confirm the exact limit for MSN.