Oh, it's even better than that. If you look at the cloudemailapp source code, the client testimonials list from the mailgun source is there, just commented out:
They also are using the exact same generated Optimizely JS file on line 9.
What's really shocking is this doesn't seem like just a copy of the site -- it's like a copy of the entire product, which is really amazing. I have to wonder if it even works...