How do I access groups?

In February 2001, Google acquired Deja.com, which provided a search engine to access an archive of Usenet newsgroup articles. Users were then able to access these Usenet newsgroups through the new Google Groups interface. By the end of 2001 the archive was completed with messages dating back to 11 May 1981. Shortly after, Google released a new version, which allowed users to create their own (non-Usenet) groups.