The Compare The Meerkat campaign reduced Compare The Market's cost per acquisition by 73%

Plus:
"It's also interesting to see the effect that this campaign has had on their price comparison competitors: according to Hitwise rival MoneySupermarket.com's traffic fell shed 25.2 per cent, Confused.com dropped 5 per cent and GoCompare.com fell 31.8 per cent."
Source: Amelia Torode of VCCP in her blog, 3rd September 2009
More data in her AdMap article