> A spammer needs to go through some external amount of effort to grab
> things off of a mailing list archive site (be it web based or
> whatever), but with usenet it requires no effort, they just get it,
> and since this is the easiest mechanism it is the one they are most
> likely to use.
The efforts to write/run a usenet scanner and to write a web spider
that digs out mail addresses from all web pages it visits should
be comparable. And I'm pretty sure there are already spammers out
there who do this.
-Andi.