No.

Writing down a loss on a purchased company is not a taxable benefit at all. They are writing off goodwill and intangible assets which were acquired when they purchased a company, and this has no tax consequences. Maybe if they wrote off tangible assets, they could accelerate the depreciation, but it's most likely that all of the write down is in goodwill and maybe intangible assets.

There are some cases in which you can write off intangible assets as "abandoned", but it's complex. A brief bit discussed in these two articles: http://www.cbiz.com/page.asp?pid=8872, http://www.cbiz.com/page.asp?pid=8984

Microsoft paid $6.2 billion in cash for aQuantitive. That asset is now worthless.

That is very real red ink, even though the actual accounting for it is occurring years later. It is a massive squandering of assets.

Can we say "congrats MS"!?

A mix of desperation, and having no idea of what you're doing. Hats off for Steve Ballmer

Goog payed 2B for DoubleClick right? Funny thing is that "everybody knew" who DoubleClick was, but I'd say it was hard to find someone to have hear about aQ before the acQuisition.

It may provide a tax benefit offsetting the sales of Windows 8 this year, but it will definitely cost them a lot of red ink.