This was a really good explanation of "MASHUP" and the trend to let others hook data into each other and create their own product from your output.
The term mash up came from the field of music. A musical mash up is a remix of two or more songs into a new piece of music. A Web mash up is a new application that is created by pulling together two or more complementary Web-based applications and/or data sources; for example, mapping a database of known child-molesters onto a map. Every time a new person is added (or removed) from the child molester database, their location is automatically added or removed from the map.
Why should advocacy groups care?
1. Big business are starting to leave hooks out there for us to use. (Google Map) voter walking, pollution and activists lists .
2. People are building their own mashups and may only want one stream of your regular output (they don't want to pass on your entire newsletter to their users but they might pass along a feed of local river conditions, volunteer actions, etc.