The Wall Street Journal after writing five articles on it, finally closed the topic by saying Microsoft is not finally buying Yahoo! The cited reason for the break off of talks is Yahoo!'s disinterest.
The difference since the initial talks is the current urgency in the tone of Microsoft. They are offering a whopping $50 billion against Yahoo! market valuation of $38bn. Yahoo! who still backed out. This comes at a bad time, just a month after Microsoft lost to Google in a war to purchase DoubleClick. Microsoft was so intent on the take over that famed bankers Goldman Sachs have been advising them.
However, talks are still on between the two on ways to cooperate and benefit each other. Ever since the rumored news broke out, Yahoo's stock went up by 9.9%, @ $30.98 in 4 p.m. Nasdaq while Microsoft's dropped to $30.56 on Nasdaq.