All that make sense? It sounds like PopCap realized that there was a call for a brand new version of Peggle (including new stages, WoW-related backgrounds, and even a secret easter egg between Arthas and Bjorn the unicorn) that was different enough to stand as its own PC game, so they worked their coding magic and put it all together into a downloadable standalone. And much to the lament of Mac gamers everywhere, it's PC-only.
But then again, it's free, it's Peggle, and so if you haven't gotten your Peggle fix through any of the aforementioned channels yet, here's the hit you've been waiting for. If you do the math (and chart the number of Peggle versions over time), we're pretty sure that, soon, all games will be Peggle. And strangely enough, we're kind of OK with that. Peggle is really fun.