Google Groups is a service from Google that supports discussion groups, including many Usenet newsgroups (based on the buy of DejaNews, which Google acquired in 2001, and email messages donated by the University of Western Ontario), based on common interests. Membership in Google Groups is free of charge and many groups are anonymous. Users can find discussion groups related to their interests and participate in threaded conversations, either through a web interface or by e-mail. They can also start new groups. Google Groups also includes an archive of Usenet newsgroup postings dating back to 1981 and supports reading and posting to Usenet groups. Users can also set up mailing list archives for e-mail lists that are hosted elsewhere.