Repositories and Web 2.0 discusses the relative merits of existing institutional repositories and putative network level shared repositories which provide more incentives for depositers. It continues an argument in favor of network level shared repositories that Andy Powell has been making for a while.
Andy has made the presentation available on Slideshare, and Slideshare is one of the repository models he suggests in the talk.
The presentation was given at the Talis Xiphos Research Day, and Andy also liveblogged other talks at the event.
Update: I find Slideshare a good place to look for pointers when I am wondering about current issues. Presentations are often elliptical, but are also current.