I've been tinkering with a Referrers page (also designed around the same WikiPlugin), and I'm amazed at the amount of static Google generates. Now I understand why people have "nojunk" options in their referrer scripts...
The Wonders Of Teutonic Program Naming
Yep. I've finally added per-node referral tracking to PhpWiki. It's not too clever (not much filtering or sophistication) and feels like a downright hack at one spot, but I had to drill through a couple of abstraction layers before I could do it "the right way" and use a WikiPlugin to render referrals.
All in all, it's not bad. At least it's one less item on the ToDo list.