APIs That Compliment Each Other

I'm starting to see more API providers working together to attract developers to their platforms.

As an API Evangelist I look for other APIs that enhance the Mimeo Connect Cloud Print API, and try to figure out how I can leverage this, or at least tell the story.

Google Cloud Print Services Interface and the Box.net API have been two of my favorites so far. I also just finished a blog post about creating classroom training materials with Crocodoc and Mimeo Connect.

Today I saw thatRdio, the social music service announce their partnership with The Echo Nest, a music intelligence platform.

They are partnering behind the scenes, but I'm sure the API is the driving force behind this relationship.

APIs enable new types of partnerships, and even allow API providers to work together and offer a more collective value.

What other APIs do you think compliment each other, and should consider partnering?