http://searchmarketing.yahoo.com/nl/jun06tu.php

MSN's U.S. search distribution agreement with Yahoo! Search Marketing ends this month, and Yahoo! Sponsored Search listings will no longer appear in MSN's U.S. search results. Although we regret the loss of MSN as a distribution partner, it was not unexpected, and we do not anticipate a significant change in the total amount of traffic to our advertisers as a result.