del.icio.us just added an interesting new feature. Its a cool toy, and maybe a sign of brilliant things to come, but it opens up the trap door of complexity in the floor, its a sign post that from here on out the mental model will never be quite so clear again. You see del.icio.us used to be for linking to web objects, usually pages, sometimes images (suggestion to support javascript: was roundly shot down), but with the most recent addition you can now link to abstract concepts. Like a color palette, like the pantone colors.