A lot of functionality is shared among applications - like sending emails or preventing spam. In the spirit of reusing the wheel instead of reinventing it, here are nine free web libraries that you can use in your next program which will dramatically increase your efficiency.

Here's their list:

• ReCAPTCHA
• Akismet
• Services_JSON
• Smarty
• pChart
• SimplePie
• XML-RPC PHP Library
• Amazon S3
• PHPMailer

Screenshots (and code examples) are provided for several of the items as well as links to their website and documentation pages.