Web 2.0 APIs and The Tides of Technological Change
If you're looking to build a new application and thinking web services should be part of it or just interested in web services in general, you should check out the
ProgrammableWeb.com / Web 2.0 API Reference Guide. It's got a pretty complete listing of the various APIs that are available. Not all are free, but most are. As this list grows, the available functionality at your virtual fingertips grows quickly. These kinds of APIs mean you can easily glue things together to solve problems without having to reinvent everything. While there are plenty of language specific libraries available, this stuff is available to any language that can make HTTP calls and get responses. That's HUGE.