We reported here on several instances in which left wing demonstration organizers tried to pump up their numbers. It’s a pretty common thing.
However — I never saw the kind of insanely inflated numbers that are going around the right wing blogosphere. A typical left wing exaggeration would be taking a crowd that was about 100,000 people and claiming 250,000.
The right wingers have got them beaten by an order of magnitude. They’re inflating the numbers by ten- or twenty-fold.