Cortana, the personal assistant for Windows Phone that Microsoft developed to rival Apple’s Siri and Google Now, gets the limelight in a new ad that’s far from being subtle (spotted first by The Verge). The commercial for_Windows Phone 8.1 pits Cortana on a Lumia 635_against Siri on an iPhone 5s, with Cortana winning hands-down as Siri just says it cannot carry out the instructions. Well, that’s something you would expect considering it’s a Microsoft ad. Microsoft is going on the offense as it picks such a battle showcased on this ad, but it’s also a complement to Apple that Microsoft...