Earlier quoted context omitted.
There have been countless research papers on this topic, so I doubt it -- http://scholar.google.com/scholar?hl=en&q=dynamic+memory+com... . Not to mention the fact that RAM compression was quite common back in the DOS/Win95 days: http://oreilly.com/centers/windows/feat/softram/dblscan.html
Yes, and that's exactly what makes it curious. It's a technology who's always been "known", but no modern operating system has bothered implementing it. Now we got two major OS shipping it at the same time, and I can't even see a correlation with a change of hardware (i.e. i can't see RAM being lately more scarce on PCs or Macs to the point of making this feature more useful than, say, 2 years ago, or 4 years ago, or…
If you're going to end up swapping to disk most of the time anyway, the feature doesn't seem to be very useful. But with much faster CPUs, "many core" CPUs where your apps often won't manage to take advantage of the CPUs, and cheap RAM making lots of people buy huge amounts, the "cost" of using compression to offset swapping to disk seems to have dropped substantially, and the chance of avoiding swapping to disk entirely seems to have increased.