There are a number of sites taking advantage of the mapping API’s of google maps and Windows live search maps.
The obvious usage of these maps which is already widespread is as directories, enabling localised searching. The ability to link different types of media tigether via a map interface results in a fantastic communication platform. Some interesting map taxonomies are subsequently evolving, particularly through sites enabling user-generated cartography.
Eco-mmunity site use mapping technology to show environmental groups, businesses, events etc globally.
This is an interactive map recently appearing in the NY Times illustrating the damage to NYC caused by the recent floods through audio, video, text, and photgraphic media. Look here
Windows live has an interesting facility where users can create “collections”, whereby they can add “push-pins” to areas and geographically associated content and then consume it as an RSS feed.
It provides an aggregation system, publishing RSS feeds of the various “GeoCommunities”. There is a tour here with more details.