Furthermore, just because something is forwarded and something is archived I don't believe is expressly covered in copyright law.
It's not the forwarding or the archiving that makes anything covered by copyright law; it is the setting down, in concrete form, the expression of an idea.
Others could argue that postings by their very nature, when posted become "public domain", and thus not copyrightable.
Not successfully in court, I should think. How is a posting any different than the production of a radio program which is distributed by store-and-forward satellite distribution and then played through the radio station and received at your home radio? The mechanisms are close to identical in their attributes; tapes at the stations have some lifetime, timeshifting can occur, special equipment is needed to perceive the work, etc.
Finally what is the tangible difference between storing usenet postings on a hard disk for an indefinite time, or on a cd-rom, or a cd that is re-writable, or tape or any other storage device? Not very much I would argue.
If you were a ligitimate recipient of the work in the first place (i.e. got it in a newsfeed) and you store those postings for your own use or for the use of others on that node in the store-and-forward network, then you can keep the work 'til the bits rot. Infringement occurs when you copy those bits onto some medium for some purpose other than store-and-forward propagation or the allowed fair-use exceptions; stuffing articles on a CD-ROM and selling them falls into neither category and hence is an infringement. Jason