>ISPs decommissioned their news servers

Yes, this is the number 1 reason.

But USENET is still being used and there are many people still using it. And there are places where you can signup for free access, this is one but there are many others:

http://www.eternal-september.org/

One thing to remember, you never see a post from your teenage self on USENET being dragged up by your employer causing you to be fired or loose out on a job. Why, privacy still exists on USENET.

Also I guess he never heard of killfiles :) These days I have a rather large one compared to what I had many years ago. See a post you do not want to see anymore, add it to your killfile and maybe the person who sent it.