Ryan Vice gave an interesting overview of Web API to 65 software professionals.
My brief jumbled notes:
AustinApi will be having it's first meeting Wednesday, April 24, 2013 for those interested in producing and comsuming web APIs.
The HTTP PUT verb is used for idempotent actions, otherwise use POST.
"application/json" is the header for passing JSON.
Fiddler is a great tool to use for testing APIs.
The MVC4 model binder can grab values from the url, the body, or the headers.
Microsoft, to their credit, is using the open source JSON.NET serializer.
You can customize the variables returned by using a custom ContractResolver.
(return "first-choice", or "firstChoice" or "first_choice").
IAPIExplorer can document your APIs similar to a WSDL.
You can download the WebAPI "Help Pages" from nuget.
I liked Ryan's last comment about Web API bringing us closer to the "elusive dream of concentrating on business logic." (Not necessarily because I think Web API will do that for us, but it should be the focus of frameworks to remove all the mundane tasks that slow us down. Perhaps in 40 years we will get there.)