Userfly

userfly.com provides website usability testing services.

Using JavaScript, Userfly captures and records browsing data from your visitors and lets you plat it back as a movie later. To implement Userfly, developers just add a single line of JavaScript on each of their site’s pages. The service will then capture and record browsing behavior as soon as a visitor enters your web site, and continues recording until they leave the site. Userfly captures clickstream data, scrolling and mouse movements, and text entry, and it rather impressively is able to interact with some pretty heavy-duty JavaScript elements.