Pre Database
Each release that gets released will result as a record in a pre-database. This record will at least contain the time the release was released and the release name (the name of the folder that contains the files of the release). The size and nature of the release are often provided too. Nukes are linked with their release in these databases when a nuke is issued. To check if a release is nuked, a scener uses an IRC channel to query the database by typing commands. These IRC channels are called pre channels and are often not accessible for the general public. The database is updated automatically through spidering topsites or by catching pre-release announcements from site channels. The purpose of these different worldwide and mirrored pre databases is to check for fakes and that for example a music album or movie isn't pred more than once and thus reducing traffic.
Read more about this topic: Nuke (warez)