AllMusic
Allmusic, which was known as All Music Guide (AMG) before, is a database about music. It is owned by All Media Guide. All Music was created in 1991 by popular-culture archivist Michael Erlewine and mathematician Vladimir Bogdanov, Ph.D., as a guide for people who wish to buy music. They have published a book every year since 1992. All Music was created before the World Wide Web and was possible to consult first as a Gopher site.