The ever-innovative University of Pennsylvania library is piloting a new social bookmarking system (like del.icio.us or CiteULike), in which the Penn community can tag resources and catalog items within its library system, as well as general sites from around the web. There’s also the option of grouping links thematically into “projects,” which reminds me of Amazon’s “listmania,” where readers compile public book lists on specific topics to guide other customers. It’s very exciting to see a library experimenting with folksonomies: exploring how top-down classification systems can productively collide with grassroots organization.