The Yellowstone Volcano Observatory has released a new in-depth article and podcast discussing the recent earthquake swarm under Yellowstone Lake. The article doesn't reveal any new analysis, but does provide an excellent summary of the earthquakes up to now and offers some helpful background information.
This Salt Lake Tribune article also provides some useful information; it suggests that scientists are leaning towards a geothermal explanation, but aren't ready to draw any formal conclusions yet.
We will probably have to wait a while for the analysis; with the swarm tapering off, at least for the moment, some of the urgency is gone, and the scientists can afford to make a more careful analysis. No obvious change in geyser or spring activity has been observed as yet; however a more careful survey will have to wait until spring.
Unanswered, for now, is whether these quakes are due to volcanic pressures, geothermal energy, or the more normal geophysical stresses of the faults in and around Yellowstone.
(The Yellowstone Park region is no stranger to earthquakes due to more familiar forces - one major quake happened west of the Park as recently as 1959. Personalizing the Earthquake Threat has more information.)