7digital enables a lot of digital music stores and provides a lot of services for mobile operators. 7digital has relationships with many labels and thus faces complex metadata issues. I’m quite pleased that 7digital has chosen to partner with MusicBrainz to fix these metadata issues.
The Echo Nest provides tons of digital music services and is a driving force behind Music Hack Days here in the States. The Echo Nest also created project Rosetta Stone, a service that translates to/from MusicBrainz IDs from/to other ID spaces like the Echo Nest IDs or Rdio IDs.
Welcome to the MusicBrainz ecosystem!