Astroturfing is the term used when someone counterfeits a grassroots effort. Instead of being forwarded by people, it's being propped up by outside interests.
Very recently the largest ever discovery of astroturfing took place. According to the Wall Street Journal Online, the people behind NannyCulture.com ordered a multitude of documents from the IRS using the Freedom of Information Act, detailing the finances and management beind various tax-exempt organizations and pieced together the links. The evidence is available at ActivistCash.com.
Or should I say, WAS available. As of this time, both the ActivistCash and NannyCulture web sites are down. Overloaded? System crash? Or were they hacked?
UPDATE: The site is back up. Go take a peek.