The disparate group of bands, zines, and fans worldwide that support heavy metal by trading tapes, zines, and gossip through the mail. The underground could be considered the antithesis to corporate rock music, records sold in malls, and advertising for bands in Rolling Stone and on the sides of busses. Aside from photocopied zines, fliers included in postal exchanges are a popular method of exchanging news or advertising new records or demos. Before the Internet, people used postal mail and the stamp trick to communicate in the underground. Now email, web sites and MP3 files have partially supplemented paper mail.