Was it just yesterday that the API was going to take over the Internet and turn every site into an endless remix of data from hundreds of freely available data stores? The world is a bit more mature now. The APIs are still proliferating, but they're not wide open and ready for anyone. Most of the better tools are following the lead of Google and imposing a fee on serious usage. Experimenting is usually free, but making more than a smattering of calls to the API requires an account and a commitment to pay.
Here's a collection of 12 APIs that caught our attention. They're modern tools for adding a little oomph or pizzazz to your site.