One of the most interesting papers I've read in that past year was recently published by Sean Gibbons in Eric Alm's group at MIT, titled Two dynamic regimes in the human gut microbiome.
In this paper they analyzed time-series data from the human microbiome, tracking the abundance of different bacteria over time (using a commonly used method called "16S"). What they were really interested in was figuring out how bacteria tend to behave over time. Specifically, do bacteria tend to stay at the same abundance over time, or change in abundance over time (and if so, change in what way?). The figure below is from their paper, and it gives you an idea of how a single bacteria might change over time. The top-left image shows a bacteria (also called an "OTU" in this case) which keeps the same abundance over time. The bottom-left image shows a bacteria that is "conditionally rare" – it bursts onto the scene out of nowhere and then disappears immediately (like The Buggles).
I'm not going to pretend to understand all of the math that they used, but the big take-home I got from this paper is that bacteria tend to stay at the same abundance over time, perturbed periodically by the "conditionally rare" newcomers, but ultimately reverting to their prior state.
This finding is a nice demonstration of a phenomenon that has been hinted in a few different experiments: that each person's microbiome tends to be stable and persistent over time. As researchers and companies try to develop techniques for manipulating the human microbiome, it's worth keeping in mind that the microbiome seems to be fairly stable, and we don't really know why.