userfly.com, a startup that launched about 3 months ago, is a new way to study user behavior on your site. The service lets you record your site’s users’ actions and then play them back in your own browser. You are able to see exactly what people are doing, which includes mouse clicks, keystrokes (except for those in password fields for obvious security reasons), page scrolling and navigation across multiple pages. Everything happens as if you’re browsing the site yourself, except the actions you see follow another user’s recorded session.