This post give's an overview of the configuration associated with Explore Mode (formerly the Experience Explorer) in Sitecore 8. It's the first in an ongoing series taking a deep dive into this feature. For more general information, read my introductory post.
In Sitecore 8, the Experience Editor has an "Explore mode". It allows Sitecore users to impersonate visitors to their website, and provides an easy means of experimenting with marketing features to see how the site would behave in different scenarios.