May 30, 2007
Here is how Google descibes mapplets:
When a Mapplet is enabled by the user, Google’s servers will fetch the Mapplet source code from your web server, and then serve it to the user from gmodules.com. To reduce the load on your server, gmodules.com will cache your source code for several hours.
There are lots of mapplets already available or you can make your own. Some existing ones include statistical information, trends around an area, movie times, and real estate information for a given location.
Publish your own to get people utilizing your site/data.