Google bought reCaptcha. For the technology or for the click-trails? After all, they already know all the "monetized" blogs you visit and how long you spend there, because the "Ads by Google" hits tell them. But what about those pesky free-lovin', non-advertising, un-google-hosted blogs that don't generate hits on google servers? Thanks to the ubiquity of comment-spam, now those hits will phone home to the googlemind, too!
This could be fun ... I'm imagining smart-ads following my pheromone trail, trying to cross it with similar ones, hoping to steer me gently toward familiar-smelling products and services. And I've got a python script pretending to be me that's randomly generating hits to some totally nutty interests ... as if it's firing flares and chaff out of my fleeing browser. And now two bots are having a completely meaningless conversation because they don't understand real human behavior. Wait, now I've gone full-circle. :)