Aside from the Modernist Journals Project, it can be difficult to see online copies of the small-press publications where much of the experimental literature has happened over the past century or so. That's why Eclipse is a useful web site.
Eclipse is "a free on-line archive focusing on digital facsimiles of the most radical small-press writing from the last quarter century. Eclipse also publishes carefully selected new works of book-length conceptual unity."
Maybe someday these archives will be as user-friendly as Issu, or one of the other PDF-sharing websites out there, but for now they serve as an excellent archive of the work.