eMarketer estimates U.S. digital ad spending will rise 14% to $41.9 billion in 2013 -- and that $7.7 billion of that total will go toward mobile ads. The research group also estimates marketers' desktop ad spending will peak at $35.39 billion next year, up from the projected $34.29 billion in 2013. By 2015, desktop spending will drop slightly to $35.26 billion, and will decrease further in 2016 and 2017, when it's expected to total $32.51 billion.

Will Critchlow, who previously mocked voice search technology, finally came around. Admitting that he has been wrong in a post, he finally sees voice search "as part of the future," and tells us how. He also provides tips to marketers that provide insight into the underlying technology. Amen. Read the article here.

Google has acquired the mapping company Waze. For now, its product development team will remain in Israel and will operate separately. A community of drivers share real-time traffic and road alerts and actively report events, hands-free, giving drivers the fastest route and reroutes during traffic snarls or detours.

Impulse buying -- a marketer's dream -- doesn't happen often enough for many brands. As James Tipton explains, while a consumer's first exposure to a brand may occur through a display ad impression, he/she may take zero action, but it does create awareness. The next time the consumer sees a banner or a text ad they will likely recognize the brand and perhaps consider making a purchase. Marketers won't know unless they use attribution modeling. Tipton explains how in this article.

Marc Andreessen, co-founder and partner at Andreessen Horowitz, funded a robotics startup called Anki that Apple CEO Tim Cook introduced Monday at the company's Worldwide Developers Conference. Anki uses the iOS devices and platform to bridge the gap between artificial intelligence and robotics. "Keeping my mouth shut about this company for 16 months has been one of the hardest things I have had to do since we started our firm," he wrote in a blog post.

David Mihm serves up insights on the way Google creates business listings and how marketers should fix the information when incorrect. Government and information across the Web, including Map Maker, create the listings, but it's the job of the business owner to make sure the information remains correct. This will help businesses move past the Yellow Pages to rethink the Web. Read the article here.

Since the most recent rollout of Google Penguin 2.0, marketers are turning toward the engine's Disavow Links tool to "bail" them out. The tools tells Google what backlinks to ignore. Sadly, the tool doesn't work, according to Chuck Price, who offers another solution. Before using the Disavow Tools, Price suggests conducting a link audit, analyzing the link data, documentation, and link removal through email outreach. He takes us through the process. Read the article here.

Search the Internet through content lenses. University of Washington professor and Google Glass project founder Babak Parviz wants to build content lenses with all the functions of a wearable computer. He wants to make a wearable contact-lens display that can do all the things Google Glass can do. To make it work, they needed a flexible, yet transparent, highly conductive material. Rather than get into the details, read the article here.

Photos and questions get more "likes" on Facebook, according to a KISSmetrics infographic. In fact, photos get 53% more, 104 more comments, and 84% more click-throughs. One study found that readers tend to like more posts with photos. The infographic also tells us the number of characters that tend to attract more readers, the time of day that is optimal to post, and how many posts per day. Read the article here.

Christina Hall gives us the lowdown on comparison shopping engines and why search marketers should care. Sites like Amazon, Google Shopping, Bing Shopping and Shopping.com collect product and pricing information from different retailers, and displaying this information on one results page, according to a consumer's search query. There are new sites like shopittome.com surfacing daily. Hall tells marketers how to begin working with the sites and set up product feeds, and outlines the ways to determine the best strategy for a specific product line. Some product lines may work better on some sites than others. Read the article here.