MSFT has been seriously trying but it ain't so easy, esp. since they came so late to the game. Swallowing YHOO is MSFT's fastest route to become a strong No. 2 in online search ads, even as GOOG continues to increase its lead over both MSFT & YHOO.
Had GOOG not bought YouTube, GOOG would still be a distance second or third in online video instead of the dominate Numero Uno.