http://www.dashler.com/toolbar/
Dashler Toolbar is a bookmarklet that opens up a toolbar of shortcuts to various webpages, and allows for super easy bookmarking. You can open the toolbar, highlight content, then open up a floating window of the results on any of (currently) dozens of websites, like Wikipedia, IMDb, various dictionaries, translate, etc. Some shortcuts use the URL or Domain of the page you are at. For example, you can jump to Quantcast/Alexa results for the page you're viewing, shorten the URL, or search within the site with Google and ilk. [Advanced: For shortcuts that use a URL, you can drag and drop links onto them to activate that shortcut. While dragging a URL, eligible shortcuts will turn green.]
The toolbar is customizable via drag and drop. You can drag and drop to re-organize the toolbar and/or add shortcuts and tools. Use "Quick Find" to find shortcuts for sites you're interested in, or related to the page you're viewing. For example, there are some neat HN tools (threaded comments, sort by hotness, etc) that I use daily. To add them, search for "HN" in quick find, or open the toolbar at a HN page and click "find related shortcuts". You can create folders / subfolders and organize your toolbar to your hearts content.
Dashler Toolbar also works well for managing bookmarks. You can bookmark the current page from the Main Menu, or you can drag and drop any links on the page you're viewing. Title and tags will automatically be pulled from Delicious, and you can instantly search for anything you've bookmarked by URL, title, or tag.
Finally, it works on all modern browsers. Create an account in seconds (no e-mail required, just username and password), and have a synchronized toolbar across all computers and browsers.
Let me know what you think.
It could benefit from some UI design - the icons are rough and there is too much stuff crammed on the menus.
I hope you're tracking which buttons people actually click and use. Use that analysis to streamline the UI and remove underused items.