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CDDB compact disc database
CDDB was invented as a local database which was delivered with popular xmcd music player.
In March 2001, CDDB, now renamed Gracenote, banned all unlicensed applications from accessing their database. New licenses for CDDB1 (the original version of CDDB) were not available anymore, as they wanted programmers to switch to CDDB2 (a new version incompatible with CDDB1 and hence with FreeDB).
After the commercialization of CDDB as Gracenote, many media player applications switched to FreeDB, but continued to refer to the service as "CDDB" as a generic term.
It is still common to see many applications refer to CDDB in their documentation when in fact the application is using FreeDB.