It would be neat if you could see a timeline of when your bookmarks were created in a linear format. Ideally you could zoom in and out. At the most granular level, you could see bookmarks that were added on a second-by-second basis. Perhaps the bookmark could be represented as a few words or as a thumbnail of the image associated with it, etc. As you zoom out, bookmarks would begin to cluster together and then you'd just see something like (12), indicating that 12 bookmarks were created within this time block.