While WordPress is naturally great for all websites, many people use
other services. Facebook, Twitter, Google, Flickr, Foursquare… All
of these various services have something in common; they usually offer
APIs of various sorts for connecting to them. You can use parts of the
core WordPress code to make that sort of integration easier to do in
themes and plugins, and to simplify much of your custom development.
Learn some tricks with making HTTP calls, OAuth and why it matters,
and how to connect to various parts of the WordPress core to do
interesting things.
