Microsoft is enabling access to a broad set of Windows Live Platform services with a separate, easy-to-understand pricing model based on the number of rare users (UUs) accessing your site or Web application. These terms are intended to remove costs associated with many Web applications and supply predictable costs for larger Web applications. There are some exceptions to the UU-based model: (1) Search: free up to 750,000 search queries/month, (2) Virtual Earth: free up to 3 million map tiles/month; and (3) Silverlighttm Streaming: free up to 4GB storage and unlimited outbound streaming, and no limit on the number of users that can view those streams. Beyond these limits websites and users will be due to conclude commercial arrangements for these services with Microsoft.
Original post by searchengineblog