The bank holds regular sales of unredeemed items, besides next week's special spring auction.

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In some countries, LivingSocial also keeps proceeds for unredeemed vouchers but it doesn't for most of Europe.

WSJ: HEARD ON THE STREET: Groupon's Terms Not Endearing

And while Groupon gives U.S. merchants their share of unredeemed vouchers, it keeps all such proceeds abroad.

WSJ: HEARD ON THE STREET: Groupon's Terms Not Endearing

Cash equivalents have become increasingly popular, but gift cards too involve waste: In one recent year, Consumer Reports said 27 percent of these went unredeemed.

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There is some art-world satire, which is gross knockabout stuff, and lists of the best names to drop frequently occupy up to half a page of unredeemed showing-off.

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Consumers generally don't get their money back from unredeemed vouchers.

WSJ: HEARD ON THE STREET: Groupon's Terms Not Endearing

Also an issue: how unredeemed vouchers are treated.

WSJ: HEARD ON THE STREET: Groupon's Terms Not Endearing