"Yahoo is a really great company, but I think they have to do something with Microsoft or Google is going to kill them," Icahn said in an interview with CNBC on Friday. Icahn was appointed to Yahoo's 11-member board after he agreed to drop a proxy challenge that would have required Yahoo's shareholders to choose between Yahoo's existing board and a slate selected by Icahn. Two of Icahn's nominees, Frank Biondi Jr., a former chief executive of Viacom, and John Chapple, a former chief executive of Nextel Partners, were also appointed to the board as part of the settlement. The meeting comes as reports show that Google is continuing to gain market share. According to comScore, Google carried out 63 percent of all Internet searches in the United States in August, compared with 20 percent for Yahoo and 8 percent for Microsoft. On Thursday, Google is expected to begin selling advertisements to run alongside some of the searches conducted on Yahoo.