I think there are a lot of broad arguments made for what is essentially a personal choice. Dave, your thoughts on the state of poetry are exactly right– there’s not much money to be made, and GPL- or CC-licensing your work does make it easier for someone else to “advertise” you. For some writers, that will be the best course of action, because they are aggressively looking for a greater audience. Others will remain fiercely protective of the current literary publishing system, and won’t want work re-distributed.
I see both sides quite clearly. Depending on the day, you’ll catch me siding with one or the other; some days I wish I could get my work in front of more people, some days I feel like I should buck it up and work within the current system, which isn’t entirely flawed and has significant merits. I’m still snobby enough that, if I have limited time to read, I’ll generally select the book from Ecco over the blog or the book from Lulu. (And I say that as a small press publisher, who is hoping to get his books in front of readers who prefer those Knopf or Penguin releases.)
The publisher side of me would be furious to find whole poems from the short books my authors produce in a form that the author didn’t authorize. The avid reader side of me has been known to pull a poem or two from a book I adored and post it to my blog to illustrate some point I’m making (perhaps a point about why I loved the book), figuring that it can’t do anything but help sales.