In the July edition of the Search Engine Report, Danny Sullivan has published this useful overview of various emerging services which attempt to harness the contributions of volunteers or relevant communities to build web directories. These include Zeal, Wherewithal, Clip2, Octopus, Quiver, and Hotrate.
They all have different twists and different flavors. For example, some are more like bookmarking services and are built around the notion of users sharing collections. Others are basically ODP (Open Directory Project) copycats, but if you want that, isn\'t there already the Go Guide?
For more of my own comments, see Traffick Notes.