First of all, CommunityWalk is a Google Maps API site run by Jared Cosulich, a software engineer in San Fransico. (Currently, it will crash Safari, but Jared says he's fixing that.) Here he explains the general idea of the site:
Despite [the Internet's] ability to make the world seem so much smaller, the Internet has done surprisingly little for the smaller worlds around us; for our neighborhoods and communities. The idea for CommunityWalk was founded around these thoughts. When Google released its Google Map technology and Paul Rademacher hacked it, presenting the world with HousingMaps, a mashup of Craigslist and Google Maps, I saw the potential to bring my idea to a reality. Initially the idea was to make a site that allowed realtors to describe the communities around their listings. My mother, a realtor, saw great potential in this idea and has been using CommunityWalk for her listings ever since. As I developed CommunityWalk, though, I realized that CommunityWalk could be made customizable, providing a means for other people to share their communities. In fact there is no reason that CommunityWalk should be limited to local neighborhoods, it can easily be used to show the community of Major League Baseball Ball Parks in America or the community of dive sites that exist at a given lake.
On the morning of October 8th, following the Paksitan/Kashmir Earthquake, I reached to CommunityWalk as my tool of choice for making information about the disaster publicly available. So, OK, I've got all this information in there and you can add some too if you want. How can you, personally, get this info out again and deploy it as a Google Earth overlay?
(Note that the following instructions work as well for a CommunityWalk map showing the location of your cousin's wedding and reception as they do for my quake info.)
The files Google Earth uses as overlays are called KML files and have a ".kml" at the end. KML is a specialized type of XML and stands for Keyhole Markup Language.
Exporting from CommunityWalk to KML is pretty easy. Click on the Share button on the lower right:
￼... and then click the Google Earth button:
￼A KML file is generated which can now be used as an overlay in Google Earth. Note that at no time did you lay hands on Google Earth itself. Now, Google Earth's people swear that their Macintosh version is coming out real soon now. But until that time, Mac users can't operate Google Earth.
But with CommunityWalk, you can make, on a Mac, overlay files for your friends (or relief organization or garden club) who can use Google Earth. Neat, huh?