Experts Exchange definitely used to do rot13 and for sure do javascript windows. Plus, it's always within a few results on Google. There's no way he can possibly be talking about some other site.
My favorite feature of Experts Exchange? If you scroll down past all the "encoded" comments (which now just say "All comments and solutions are available to Premium Service Members only."), and past the LONG list of topics, what do you find? The unencoded comments with the solutions ;)
There was a time I remember this being true. A few weeks ago I stumbled upon an experts-exchange result and decided to see if it still worked--it didn't. So, I'm guessing this doesnt' always work.
From the horses mouth: "Stackoverflow is sort of like the anti-experts-exchange (minus the nausea-inducing sleaze and quasi-legal search engine gaming) meets wikipedia meets programming reddit"
(edit: admittedly this is still speculative)