Trailmeme - unique concept. bookmarks stored as "trails;" can be fun to make. good for sharing but poor for organizing. clunky bookmarklet.

getwapps - allows for personalization. bookmarks are presented visually with screen captures & with lists. no bookmarklet.

currently evaluating social bookmarking sites.

Pearltrees - unique site layout; would be better if "pearls" could be moved around. good Firefox plugin. can't add stickr to site.

attractive site layout.

bookmarks are stored visually.

bookmarklet / plugin for Firefox is poor.