An enterprising spammer apparently has created over 5 billion pages and gotten Google to index them, in only 18 days. The pages carry Adsense (Google) ads, and apparently by spamming blogs they are getting enough cross-links to get ranked and hit in searches. The business model is to steer hapless searchers to totally useless pages and get Adsense clickthrough revenues.
The idea isn’t new, but the scale is pretty astonishing. The Monetize blog article linked above includes step-by-step instructions on how to do this. A pernicious type of pollution, and it looks like it may be growing exponentially: a problem begging for an incentives-based solution!