Discussion group service provided by Google
Google Groups is a discussion group service from Google. Alongside the groups and discussions created by the users, it also includes Usenet newsgroups.
Groups can either be invite-only or open to the public, or, if the group is created within a Google Apps for Business domain, open to users of that domain.
The service started out as Deja News before the transition to Google Groups following a buyout in 2001.