http://www.comcast.net/newsgroups/
http://help.comcast.net/content/faq/Does_Comcast_offer_a_newsgroups_service

Since I've been a Comcast subscriber, Comcast offered Usenet outsourced
to Giganews. This was discontinued effective September 16th, although
it won't be discontinued for existing users until October 25.

If you're a Comcast subscriber, please complain. I called customer
retention (the sales group you get when you call their customer service
number asking to disconnect service) and told them that Usenet was worth
$5 a month to me and they gave me a credit for each of the next 12
months. It's unlikely to change anything but it's more likely they'll
notice if a customer requests a credit.

For binary Usenet, http://giganews.com/ or another premium service

For text Usenet only, http://individual.net/ is the best there is.

Also http://aioe.org/ http://www.motzarella.org/

There are alternatives. Don't use Google Groups. Don't lose access to
the most important newsgroup on Usenet.