Usenet's main purpose was as a group discussion forum, much like LJ or other web forums are now, except, well, better. Distributed and message oriented, I think it's still a better mechanism for forum style stuff than the web. Usenet was hijacked by rampant filesharing a number of years ago, with the volume of spam and shared media files dwarfing the volume of actual communication. I wonder if that precipitated the death of usenet, or if that kept usenet going longer than it otherwise would have.
Regardless, and great source for discussion and easy to download porn is now gone for rogers customers. It is the end of an era. It used to be that every ISP hosted thier own news server, and had someone responsible for looking after it. This meant that when one wanted to read USENET (aka "news" over the NNTP protocol), one only had to connect to a local server, much like mail is for most people (though this, too, is changing). This is what made it so attractive as a file sharing tool - since the server was only ever one or two hops away, internal to your ISP, it was typically a much higher speed connection than one had to servers off of one's ISP's network.
The whole concept of ISPs providing anything more than a fast connection seems to be dying off - even for mail, rogers farms out to Yahoo. This trend has some customers peeved, as the article mentions, since the ISP is charging the same, but providing less. On the other hand, how many people use thier ISP email as their primary account, as opposed to, say, Gmail or something else? A big part of this, I think is the increasing ubiquity of internet connections - most people have them at work now, and in most big cities, one can find wifi hotspots (free ones are harder to find, but still...), and people want to have access to thier email, etc. from wherever they are, whichever computer they're using.
My theory, then, is that decentralization and widespread net access has pushed web forums like LJ, and killed usenet as a discussion forum, leaving it as a porn farm - though even then, p2p has been replacing that function.
(I realise that they are still going to be people out there using it, but unless I decide to pay for a giganews feed, I am not going to be seeing it)