Chrome: Even when you organise your bookmarks neatly into folders and subfolders, if you've got a ton of bookmarks, they can be hard to access quickly -- and easy to forget about. Stashmarks solves this problem by indexing your bookmarks and making them searchable.
The web app/extension lets you search not just the title of each of your bookmarks, but the content of the bookmark as well. Once you sync your bookmarks to Stashmarks, you can search your bookmarks from any computer to find that page you had bookmarked long ago whose site name or page title you forgot.
Stashmarks automatically tags your bookmarks with the name of the folder you place your bookmarks in, and you can also add tags and edit the bookmark title as well from within the web app.
The service is currently in private beta, but the first 2500 Lifehacker readers to sign up via the link below will get an invite. I found the service pretty easy to use, and the developers are hard at work developing the app (the tag adding is new, for example). Let us know what you think in the comments.