On collective marginalia

The "Popular Highlights" section on the Amazon site as drive by the Kindle highights of users is rather nifty. Wouldn't it be nice to also have more insights and statistics on those? Of course there are privacy issues, but I would love to drill-down and see what others have highlighted, or read comments. Which brings me to another point - how we could we make leaving comments attached to your highlights easier? Is there some service where you can ee your own highlights online and annotate the,? Now THAT would be a killer application for studying purposes.

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