I get what you're saying, but the guy in the article is talking about renting an "extra bedroom in a nice neighborhood". Look at that guy's place -- he's got a duplex penthouse in what appears to be fairly nice shape with at least 2 bedrooms. Most likely substantially more than $1000/mo.
I have a two bedroom condo and use one of the rooms as an office/storage. After reading this article I am seriously considering moving my desk to my bedroom and getting rid of some other stuff to make a spare bedroom.
I'm sure there will be some hassle dealing with guests, but it seems pretty close to "free money" in my opinion.
While I have over $10k in savings, I don't have so much money than I can just throw $10k of it into risk. I don't think I'm that uncommon.