An aspect that the blog post did not get into as much is what does it mean for something to be a computation or a simulation. Formalization of computation is well trodden ground.
Lets take the state transition view of it. Our PCs, phones or any other physical thing that we agree is a system 'that computes' is just following the laws of physics, or state evolution. We engineer the initial condition so that it converges to something that is of interest to us. So does it mean it is necessary for the existence of a conscious observer / intervener / interpreter of state for something to be deemed a 'computation' ?
Even if no one is there to observe a particular state or have interest in it, if the system happens to be initialized at some state it would 'compute' the result (end state) no matter what. So what would be that fundamental difference between a simulation and a universe following physical laws ? I think the issue is not whether this is a simulation but whether someone is consciously simulating it. The thing is that it need not be an external entity, embedded entities themselves may reside (perhaps voluntarily) in a simulated experience (hallucinogenic drugs), insanity (socially imposed conformance / compliance), schizophrenia.
The notion of reality is messy business that ties one up in knots. What I find interesting is how two ancient cultures : (i) native American and (ii) Indian thought about it, how they answered when I am dreaming is that real or is that fake. It is really hard to argue that what we call real is a more privileged position than the dream world or a hallucination when we are in it. Some native American philosophies decided that both are equally real. If some one flies in a hallucinogenic trip the person is really flying in that world. There are ways to get in and out of those worlds. The ancient Indians or the vedic philosophers took another route, they chose that both these worlds are just equally unreal.
The question of whether this real or not is pretty much as old as thought.