What are gadgets?
Simple to build
Gadgets are simple HTML and JavaScript applications that can be embedded in webpages and other apps. Built-in JavaScript libraries make it easy to create gadgets that include tabs, persistent storage, dynamic resizing, and more.
Multiple sites
Your gadget can run on multiple sites and products including Gmail, Calendar, Sites, Maps, or any webpage. Write your gadget once, and with minor changes it can run in multiple places.
Reach millions of users
Many gadgets are viewed millions of times per week and generate significant traffic for their authors. Gadgets can also be included in applications listed for sale in the Google Apps Marketplace.