Since Google bought the Deja News Usenet archive and web interface in 2001 they have mixed their own Groups into the melee, but do not publish those Groups' posts back to Usenet.
However one can still read and interact with Google Groups through the mailing list functionality, even without a Google Account.
- Find the non-Usenet Google Group you wish to follow
- Click the About This Group link and note the Group email string. Don't worry about the statement Only members can post as you are about to implicitly become a member.
- Create an appropriate e-mail alias for yourself and send an e-mail to an address constructed by prepending "subscribe+" to the e-mail address found in the step above e.g.
- Wait for the subscrpition confirmation e-mail back from Google and reply directly to that e-mail; do NOT click the Join This Group link in the e-mail body!
- Volia, you are now subscribed to the mailing list for the group! You can read and reply as with any other mailing list.
Of course this does mean that you are leaking some information about your interests back to the Mighty G. Perhaps you should subscribe to Modern Lacemaking along with 80s Punk, just to maintain a skew.