PHOENIX--During the hands-on sessions at Demo, I checked out Plum (still in closed beta). This service lets you collect things you like--bookmarks, photos, documents, etc.--and then use those collections in several useful ways. The service acts like a social network of knowledge: If there's an item in your collection, the system can tell you what other people who have the same item also have in their collections. In some ways it's like Del.icio.us, but the user experience is more mainstream (i.e. easier) with Plum.
In Plum, you can tag items, just as you do in other bookmarking systems. But the founders of Plum recognize that many users may not tag their content, so Plum also performs a contextual analysis of your items, and groups them based on that. Plum can display its items on a Web page (in several different formats) and also send you items in e-mail or RSS feeds.
Plum lets you collect items from your own computer, and intermingle them with your bookmarks. I saw a demo of saving a photo on a local machine to a Plum account, and it was much easier than any of the online-only bookmarking systems I've seen. It's also easy to publish and share a collection (or just a narrow slice of a collection) with other users, so Plum may end up competing with photo-sharing services.