This looks fantastic, I've just enabled it and it's nicely grouped the things I was looking for yesterday.<p>To quickly answer the first thing I looked into here, it doesn't send any of your data on (there are some google analytics stuff, but it doesn't send on your browsing history).
I'd give my right arm for something that did this auto-magically for my bookmarks.<p><a href="http://cottontracks.com/" rel="nofollow">http://cottontracks.com/</a>