Blummy is an organizer for your bookmarklets, customized easily, quickly, and precisely for your needs. The result is that you get a ton of convenient, time-saving features that only take up one button's worth of real estate in your browser's toolbar.
Ever post a comment on a blog, then forget to go back and check the post to see how the conversation continued? Co.mments makes this easy. You can even set up an RSS feed to be updated when new comments are posted.