Following the Yahoo! board of directors decision to turn down Microsoft's $44.6 billion buyout back in May, some of Yahoo!'s higher profile investors have been left understandably annoyed. None more so than high profile billionaire investor Carl Icahn, who has been quite open in his plans to oust the current Yahoo! board in a proxy battle, replacing them with Microsoft-friendly directors, and hopefully sealing a merger between the two internet giants. Icahn's major point of contention lies over claims that Jerry Yang, Yahoo! co-founder and current CEO, effectively sabotaged the Microsoft takeover bid with Yahoo!'s employee retention system. In a letter to Yahoo chairman Roy Bostock last week, Icahn brought the complaint that, "Viewing employee retention as Microsoft's Achilles heel, Yang engineered an ingenious defence creating huge incentives for a massive employee walkout in the aftermath of a change in control.