Informative astroturf sends a lot of the same form letters to some politician so that politician can count up how many people support the point of view.
Deceptive astroturf disguises its form letter as a personal, heartfelt opinion, sending one copy (each signed by a different person) to each of many newspapers or individuals. The recipients aren't meant to guess they are reading a PR firm's carefully-worded message. Propagandists call this way of disarming suspicion the "Plain Folks" effect.
The irony is the Bush team is sending out astroturf with intent to deceive--after denouncing and refusing to consider more than 700,000 messages sent to them in an open, appropriate way by members of environmental groups--because they were form letters and not "original."
Check out this New York times story, sent to me by my environmentally-friendly daughter Mickey. Registration (free) is required, so let me just quote for you the astroturf-relevant bit:
"... the [Clinton-era] Forest Service actually relied on public comment when it developed its "roadless rule," intended to protect 58 million acres of undeveloped national forest from most commercial logging and road building. It drew 1.6 million comments, the most ever in the history of federal rule-making. Almost all the comments -- 95 percent -- supported the protections but wanted the plan to go even further, which it eventually did.
But the Bush administration delayed putting the rule into effect and sought more comments, receiving 726,000. Of those, it said that only 52,000, or 7 percent, were "original," meaning that the administration discounted 93 percent of the comments. The rule is now being challenged in court."
Update: Paul Boutin's excellent blog just got updated with links to deceptive astroturf online as far back as October. Meanwhile, Mike Magee got in trouble and issued a funny apology for referring to these mass-mailings as "spam." Really, Mike, just because they are mass-produced mailings with intentionally deceptive statements of origin...