Mush
Sean Gillies has been experimenting with a web service, Mush. It takes two GeoRSS feeds and calculates the “sphere of influence”, or spatial intersection, of the two feeds.
Perhaps it’s part of a trend (hopefully) for more “analytical” services in “neogeography”.
The Planning Alerts GeoRSS API was used as a clever example. In combination with a GeoRSS feed of Celtic coins, it shows areas where development activities might unearth more coins — actually sounds useful!