Essentially, the guy is showing how algorithms, that started from merely describing our reality (e.g. by means of numerical simulations), are now re-shaping our world. His conclusion is that we can't treat realms, which exist only in computer memory, as "less real" then the world of physical particles around us, as they both happen to strongly influence each other and they're both part of the very nature itself (as a consequence of whole human civilization, including all its artifacts, being a result of natural evolution).