John McKerrell discusses using crowd-sourced data from sources like Geonames, Wikipedia, and Flickr in Multimap's commercial mapping API. Wikipedia data is hard to parse but people were helpful when contacted. Flickr photos sometimes had nothing to do with the location and there was little moderation of user-submitted data. While the Flickr integration was never released, it served as a proof-of-concept for Multimap's API capabilities.

1. John McKerrell
Using Crowd Sourced Data in a Commercial
Mapping API
Multimap.com

2. Sources
Geonames

3. Wikipedia

4. Wikipedia - Implementation
Taking complete dataset and parsing it
Hosted by Multimap
Updated on a regular basis
Also available on maps.live.com

5. Wikipedia - Issues
Hard to parse
Special syntax required, people often get it wrong
Some people try to do new non-standard things

6. Wikipedia - Positives
People were really nice
Email got a quick response and initiated a phone
conversation
Aided us in meeting the terms of our license
Weren’t pushy about donating to the foundation

7. Flickr