The Flickr.Net API is a .Net Library for accessing the Flickr API. Written entirely in C# it can be accessed from with any .Net language in .Net Framework 1.1, .Net Framework 2.0, .Net Compact Framework 2.0 and Mono.
Are you in the business of selling video content? How will you broadcast it? The Applicaster API aims to help answer that increasingly complex question. Where once it was a matter of getting on a network, now it's an issue of delivering experiences over mobile, synching, caching and live streaming, coping with connectivity issues, and providing an Airplay experience.
Snipt is a web service that attempts to solve a simple problem: storing commonly used snippets of code, and sharing them with your fellow coders. It seems to do that pretty well, with lots of good options for storing and sharing. Better yet, it has its Snipt API so coders can use this simple storage engine within their own programs.