On Friday, I made a presentation at the California Trails and Greenway Conference in Folsom, CA. The theme of the presentation was bringing trail and park information into Google Earth and Maps. I talked about how the attendees and indeed anyone can publish custom content in Earth and Maps.
Why would you want to publish content to these platforms? Google Earth and Maps have hundreds of millions of users worldwide. So when make your information available to users these products, you can reach an enormous number of people in a familiar user interface.
There are a variety of techniques of authoring and publishing data, but most involve creating content that is based in KML and putting this information on a web server or the Google Earth Community. Remember that most KML content is viewable in both Earth and Maps.