GeoRSS is an extension of RSS that adds geographic data. You can use it to clearly state the location of an event you describe in a blog post. As you can see in this example, it's really easy to add a GeoRSS tag to a feed. To get the latitude and longitude for an address, use Address Fix.

There's also a nice RSS to GeoRSS converter that identifies locations in a feed and transforms them into geographical coordinates. Here's how to use it:

http://ws.geonames.org/rssToGeoRSS?feedUrl=[RSS feed URL]

Example: Reuters World News

The reason for this talk about GeoRSS is that Google Maps started to support this format. Yahoo Maps is already using GeoRSS for data overlay; so does Virtual Earth. Google has been using KML, a format created by Keyhole, the company that developed Google Earth.

We now support GeoRSS as a data format for geographic content in Google Maps. We want to enable users to create data in whatever format is most convenient for them, and feel that by supporting both KML and GeoRSS we can enable a wider variety of people and applications to contribute content to Google Maps. We've built support for the Simple, GML, and W3C Geo encodings of GeoRSS -- all you have to do is enter the full URL of a GeoRSS file into the Maps query box to load the file. (...)

Most importantly, we've extended support for displaying geographic data -- both KML and GeoRSS -- into the Google Maps API. Now in addition to programatically adding content to a Maps API site, you can create your content as KML or GeoRSS and load it into the Map with a simple function call.

Here are the Reuters World News, some Flickr bird photos and a travel blog on Google Maps. As you can see, it's so easy to create mashups from a simple feed. </img> </img> </img>