Does it matter what time of day a mobile ad is displayed? If a generation’s worth of lessons learned from email marketing mean anything, the answer is… maybe. Truth is, there are coherent arguments to be made on both sides. However, as marketers intensify their aim at mobile devices, the balance is shifting to the side that believes timing matters. People’s propensity to use tablet devices in the evening to sofa surf — and shop — strongly suggests that it does.