Discover Android Apps to Crowd Sourced.
The book database and much of the information are contributed and maintained by the user community.
MusicBrainz is a community-driven open data music database project. It aims to provide comprehensive and accurate music metadata, including artist, album, track, and release information, serving as a central resource for music cataloging, tagging, and discovery.
Goodreads is a social cataloging website that allows users to freely search a database of books, annotations, and reviews. It enables users to keep track of their reading progress, discover new books, and connect with other readers.