Flickr is now utilizing maps from the wiki-based Open Street Map project to improve the detail level on cities where Yahoo's maps fall short. The first city to get the treatment is Beijing in honor of the Olympics. Flickr has posted before and after shots and the difference is profound. What was once a brown blob now has streets, landmarks, and of course geotagged shots.
Despite the improvement in Flickr's world map, parent company Yahoo's maps, which power the rest of Flickr's world map cartography, have not been cross-updated to share the changes. Flickr is using the data from the Open Street Map project under a Creative Commons license called attribution-share alike which allows for free remixing and distribution of the data with proper links back to the sources. Yahoo is unlikely to adopt larger portions of the project's map for the sake of consistency, although it contributed aerial photography to the project back in late 2006.
The Open Street Map was launched in 2004 as an open project, allowing anyone with proper GPS data or local knowledge of a city to contribute to the map of the world. Like Wikipedia, it has groups of people working on various areas, to edit and maintain the cartography as cities change. Presumably we'll be seeing more data being ported over to other populated areas where Flickr users have had to geotag their shots without the aid of proper local maps.