I think it's Google's automated "spiders" that guage for relevant advertising environments... they're scary smart and often pinpoint accurate.
LOL, I think Google's figured out that I like girls. I often have lesbian matchmaking ads in my sidebar.
SPIDERS! But then I wonder how come I see so many bikini-clad babes in my sidebar?
whoa! 9 degrees! That's cold! And I'm here in NJ at 30, thinking it's so cold!