This article makes me think that it's time to start to look for a new line of work. I so dislike the notion of replacing the predictable reliability of fixed resources with this vague quasi-economical logic of boom and crunch periods whose timing will depend on the dynamic demands placed on unrelated systems which nevertheless share the same resources.
The problem here is that computer systems have a minimum expectation of the availability of the various resources, and that in turn dictates the minimum which must always be available to each service, or that service will risk collapsing under load. Of course, this minimum guaranteed level looks a lot like spare capacity to somebody who doesn't realize that the system is already at the optimal minimum. (The other big complication is that throughput of complex systems tends to be limited by the most constrained resource, so screwing this up in any of the major resource categories is going to be bad news for throughput.)
However, I suppose that sometimes it is guaranteed that resource demand peaks occur at non-overlapping times. So you might put nightly backup service on the host that also services some other function during daytime, or something. It is also possible to guarantee minimal resource availability to some virtual machines and leave the rest to struggle under "best effort" guarantees. This kind of competition between resources doesn't sound anything like a "RAM market" to me, though.
I will refrain from criticizing this article much further, but I'll be personally be rather happy if there will be no more like it. RAM servers to make a tidy profit? I find the notion ridiculous and have no idea how it could really work or even make any sense.