http://www.geonames.org/ is doing something cool. They’ve compiled several public domain gazateers, including the GNS database (used in the worldKit geocoder). Smacked a search and web service interface on the front. And it’s all editable, wiki style.
There’s loads of public domain geodata published in various corners of the web. Part of the skill in being a geo-hacker/wanker is gathering knowledge of the what, where and how of these data sources. The other problem for the web at large is the inaccuracy and slow update times of these data sets. Some of the OGC and Web Service standards on resource discovery have planted seeds to address this, but haven’t fruited. Many folks have discussed doing wiki-like gazateers, and it’s very cool to see an implementation that bridges lots of these projects.
Tagzania is embracing this project, and many opengeodata projects like OpenStreetMap. By engaging with opengeodata projects and formats in a substantive way, Tagzania is really starting to differentiate itself from the ver–y crowded social map hacking space.
He’s gone with the bleeding edge Simple GeoRSS format which is not yet finalized, but is supported in its current form (though not documented) by worldKit.