OAuth is becoming a very popular way to control authorized access to Web APIs and the data that they return. Although it's one of the most straightforward ways to accomplish this, it's still rather confusing to use. If your API uses OAuth, then you need to be able to describe it so that developers can quickly understand what they need to do.
With The AP releasing an updated version of its Elections API earlier this year, news organisations across the US now have faster access to elections race information. This led NPR and the NY Times to improve on their legacy FTP system by building a new API for accessing AP information faster.