Once upon a time, Carl Icahn complained about the way Jerry Yang was running Yahoo and bought a massive number of shares to force him out. Later, Icahn joined Yahoo's board of directors and gave Carol Bartz his full support. Now, Icahn's involvement seems almost over, as he's sold around 7.9 million shares. This new development is a rather big deal. Icahn owned 11,991,000 shares of Yahoo's stock as of December 31st, 2009,