MarketingShift points out that Isobar Communications bought search firm iProspect in the latest in a series of acquisitions. Isobar is the consolidated online holdings of Aegis, the European-based ad firm that owns Carat and brags of about $500 million in internet billings. It formed in September of this year with the overly-ambitious goal of driving Aegis's growth to the extent that the internet accounted for about half of its billings by 2007.