Sources
Taginfo collects data about OSM tags from several sources and brings them together for easy browsing and discovery. Here is a list of currently used sources. More sources might be integrated in the future.
Note that taginfo only displays this data. If you want to change it, you have to go back to the source.
Database
Statistics about keys, tags, and relation types are generated from the OSM database (or an extract) as well as the maps that show the geographic distribution of nodes and ways.
Wiki
The OSM Wiki is read and all Key:*, Tag:*, and Relation:* pages (in all the different languages) are analyzed. Descriptions, images, related tags, etc. are extracted from them.
Languages
Projects
Projects that use OSM tags in some way, such as editors, maps, routers, etc.
Chronology
Number of keys/tags over time from history planet.