Letâ€™s take a look at some of the more notable deals of the Ballmer era: aQuantive. In August 2007, Microsoft acquired aQuantive, a online ad agency, for $6.3 billion cash, and 85% premium. At the time, it was Microsoftâ€™s largest deal. â€œThis deal takes our advertising business to a new level,â€ the companyâ€™s COO, Kevin Johnson, said at the time. Howâ€™d it work out? Microsoft took a $6.2 billion write-off on the business in 2012. â€œThe acquisition did not accelerate growth to the degree anticipated,â€ the company said. Skype. In May 2011, Microsoft acquired Skype for $8.5 billion in an unsolicited bid â€œeven though there were no signs of other serious bidders,â€ as we wrote at the time. The price tag was three times what the company had gone for just 18 months prior, as the company was scrambling to catch up in the mobile and Internet markets. Howâ€™d it work out? Microsoft doesnâ€™t break out Skype revenue, so itâ€™s hard to really know. But the service is popular, and they just unveiled a gee-whiz â€œStar Trekâ€ like universal translator service. Nokia. In September 2013, Microsoft acquired Nokiaâ€™s handset business, for $7.2 billion in cash. â€œItâ€™s a bold step into the future â€“ a win-win for employees, shareholders and consumers,â€ Mr. Ballmer said at the time. Howâ€™d it work out? You could argue, if you like, that itâ€™s too soon to say; the deal closed only in April. But Microsoft controls less than 4% of the U.S. smartphone market. Moreover, whether itâ€™s a win-win for employees, shareholders, and consumers, it was a definite loser for Mr. Ballmer: the Nokia deal was apparently the deal-breaker for him, and the internal fight over it led to his ouster. Yahoo. Of all the deals Microsoft did do, itâ€™s the one that it didnâ€™t do that may be the most instructive. In February 2008, Microsoft offered $44.6 billion for Yahoo, a 62% premium to the companyâ€™s stock, in an attempt to merge two struggling search businesses. It was a huge deal in the high-tech world, and it was a huge, public, messy battle that Microsoft eventually lost in one way, and won in another. Yahoo ultimately rejected the deal, although angry shareholder would later boot founder Jerry Yang over it. Yahooâ€™s stock, which was in the $30 range when the deal was announced, would soon sink into the single digits, and would languish in the teens range for years after. Not exactly a sterling record, no pun intended, and we didnâ€™t even mention Microsoftâ€™s stock, which went from $58 when Mr. Ballmer took over in 2000 to $40 and change today.