I think the concept is similar to Clicktale and even simple User testing. But instead of asking users to perform tasks you get to watch real users using your site.
Something quantifiable is nice, but after watching a few of these videos of your users, you will quickly find some of the big problems your site faces. You likely won't notice the small ones, but you should be able to see some of the big ones, which are the ones that need your greatest attention anyway.
I also would like to see their price before giving them an email.