For comparison, (well, someone beat me to this so whoops!) just checking the Bay12 (Dwarf Fortress) forums, there are 45,000 members. Some of those folks aren't even there for Dwarf Fortress, but for the community itself (I almost only lurk there for the Other Games forum myself). The 'online today' numbers for the two are 32 vs 431 (no prizes for guessing which is which). Just back-of-the-envelope-numbers-wise, Dwarf Fortress showing up on a 'big' site is less surprising than Aurora.
Aurora is also fairly niche and a bit more difficult to approach (like the resolution and installation issues), so seeing it in the mainstream is a bit of a shock for those of us who just bunnyhopped here from various corners of the Internet.
I am glad it was reviewed though; Aurora may not be for everybody, but I'm sure there's lots of folks who'll find it through PCWorld and find it to be the game they never knew they wanted.