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There are meny crawl tools out there, but Xenu is the one I would recomend for this. It will crawl your site, and then at the end ask for your ftp details so it can specificaly check for ophaned pages. That should make the report you need. *edit - here's the link: http://home.snafu.de/tilman/xenulink.html

In my opinion, duplicate content is one of those things people get unnecessarily hung up about. I think it is about control. Duplication means loss of control - Google will choose which version to display in the results. For video, keep the full or extended versions on your domain. Syndicate the teasers or ads everywhere. That way you keep control and meet the aim of driving traffic to your site

Not seen it in action, but I like it. I like it a lot First thoughts are that it'll never been usable on a massive scale (I'd be worried about security and people gaming the system for points if the rewards are any good), but for smaller sites I think it's very clever.