These are all birds of a particular feather, what the digital preservation system LOCKSS (Lots Of Copies Keeps Stuff Safe) calls "born-digital, freely available humanities e-journals." LOCKSS goes on to say, "Small publishers using marginal business models currently publish a substantial amount of important work in the humanities." Poetry in particular seems ideal for web publishing. People won't read long texts on a screen: after a couple of page-downs they will stop to consider 'Do I want to read this? If yes, do I need to print it?' But many poetic texts and other short literary forms are an inviting length to pursue to their end on the screen. It simply works to put them up on the web.
Recently there was an article in Publishers Weekly, 'Poetry Off The Books' by Craig Morgan Teicher which makes a similar point. "In recent years, poets and poetry enthusiasts have been organically developing a network of linked online poetry publications, blogs and other related sites, many produced at quality commensurate with the best print magazines." The article contains a lot of links to online literary magazines and influential literary blogs, and wonders whether all this activity is increasing sales of books as well as increasing the readership for poetry. Duh. Poets don't earn their living by selling their books of poetry. That won't change. Maybe if they do it for several decades, they'll win a big prize, as Richard Wilbur did recently. But in general, the servants of the muse are not in it for sales of books... The Wilbur story is also at poetryfoundation.org, but actually we're giving you that link because the cartoon which was in the middle of the cover page last week was a hoot.