They think the online advertising iis going to continue to grow:

Microsoft Corp. (NASDAQ:MSFT) today announced that it has made a proposal to the Yahoo! Inc. (NASDAQ:YHOO) Board of Directors to acquire all the outstanding shares of Yahoo! common stock for per share consideration of $31 representing a total equity value of approximately $44.6 billion. Microsoft’s proposal would allow the Yahoo! shareholders to elect to receive cash or a fixed number of shares of Microsoft common stock, with the total consideration payable to Yahoo! shareholders consisting of one-half cash and one-half Microsoft common stock. The offer represents a 62 percent premium above the closing price of Yahoo! common stock on Jan. 31, 2008.
“We have great respect for Yahoo!, and together we can offer an increasingly exciting set of solutions for consumers, publishers and advertisers while becoming better positioned to compete in the online services market,” said Steve Ballmer, chief executive officer of Microsoft. “We believe our combination will deliver superior value to our respective shareholders and better choice and innovation to our customers and industry partners.”
“Our lives, our businesses, and even our society have been progressively transformed by the Web, and Yahoo! has played a pioneering role by building compelling, high-scale services and infrastructure,” said Ray Ozzie, chief software architect at Microsoft. “The combination of these two great teams would enable us to jointly deliver a broad range of new experiences to our customers that neither of us would have achieved on our own.”
The online advertising market is growing at a very fast pace, from over $40 billion in 2007 to nearly $80 billion by 2010. The resulting benefits of scale along with the associated capital costs for advertising platform providers make this a time of industry consolidation and convergence. Today this market is increasingly dominated by one player. Together, Microsoft and Yahoo! can offer a competitive choice while better fulfilling the needs of customers and partners.

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