The main accusations in the lawsuits can be split into two categories: revenue claimed to be from advertising that came from elsewhere (such as legal settlements), and revenue claimed to be from advertising that was not revenue at all (such as barter deals with ads swapped between Internet sites).

ECONOMIST: AOL Time Warner

How much cash you spend on advertising depends on the market your team is in and how much you're able to barter.

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"Clearly when you back out the barter transactions, as well as the three-year dot-com ad contracts that are now expiring, advertising wasn't a viable business model, " says Henry Asher, president of Northstar Group, a New York-based investment manager that holds the parent company's shares.

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