The Scribble Map web app lets users create custom maps by adding custom content to Google Maps. Users can add lines, markers, shapes, text, and web images, all the while controlling factors like line thickness, feature opacity, font selection, and color, etc.
When you're done, send the map to a friend via email or Facebook. You can save your map online for future revisions, save the image as a jpeg, save the map as a KML, or open the map with Google Maps or Google Earth.
Scribble Map doesn't provide all the options and functionality found in a more complicated GIS software, such as ArcGIS--e.g. you can geocode with Scribble, but not batch geocode, and the app offers no geoprocessing functions. But Scribble Map lets you create nice-looking, custom maps without the time required to learn and use more complicated (and expensive) GIS software. (Also see the freegeographytools.com blog post.)