Last week saw an unusual burst of acquisition activity among Web companies. Yahoo bought email add-on Xoopit for about $20 million, Nokia bought social address book provider Cellity , and overshadowing them all was Amazon's $928 million purchase of Zappos . But the week started off with another acquisition which quickly got lost in all the subsequent news. Advertising network Adknowledge bought KITN Media for its flagship virtual currency product, Super Rewards . The acquisition price was undisclosed, but Eric Eldon at VentureBeat noted that the rumored price was $30 million (he also noted that AdKnowledge disputed that number as "patently inaccurate.") I heard the same number the night before the acquisition was announced. It was being floated by one of AdKnowledge's competitors. When I asked Adknowledge and Super Rewards about it, they gave me the same line: that it "was incorrect and it would be a material misrepresentation of the transaction." I dug around a little more and found out that the price was actually more than $30 million. A source with direct knowledge of the deal told me that it was closer to $50 million.