In 1993, the newsgroups were way too much to read even if that is all a person did, so you must mean using a program to scan the groups for URLs; right?

Google has a fascinating timeline of Usenet news:

(http://www.google.com/googlegroups/archive_announce_20.html)

Even ignoring binary groups a Usenet feed would have been considerable in 1993.

(http://en.wikipedia.org/wiki/Usenet#Usenet_traffic_changes)

Well nobody read every newsgroup, did they?

I had a core list of 4-5 newsgroups that I would check once daily. On a busy day there would be maybe 20-30 new messages per group.

After Eternal September some of those groups went to hundreds daily and got to be too much to cope with in a day.