Often this involves concealing information that would cause potential transacting partners to refuse to transact with them or to demand better terms as a condition of doing so.
The TV Everywhere initiative by cable providers is an attempt to retain subscribers by offering a choice of free on-demand viewing over the internet on the condition of subscription to their pay TV services.
Rare vintage in fine condition from top 20th-century designers is in demand, says Patricia Frost, international specialist in Christie's Costume and Textile department.
Pressure from America and Europe is not entirely ineffectual: it seems to have been the catalyst behind Mr Sharon's decision to drop his original demand that the Palestinians hand over the men responsible for Mr Zeevi's murder as Israel's condition for withdrawing.