Marketing professionals will be happy to hear recent data that backs up their water-cooler hunches: marketers in the US and UK spent more on paid search advertising in the last quarter of 2011 than Q4 of 2010. Similar growth is expected throughout 2012.And while Google maintained a cool 80% of market share, Search Engine Journal claims that 30% of all US-searches are through Bing. Plus, the Yahoo and Bing alliance (Yahoo is now powered by Bing) had clicks that were 14% more valuable than Google, while also producing 9% higher ROI. These numbers support recent comments by members of our sister site, Subscription Site Insider. At the Insider‘s Summit in NYC last October, a number of members claimed that Bing users were more important to them than Google users.We surmise (with absolutely no proof…yet) that Bing users stick to desktop pre-sets (Dell computers, for example, come preset to Bing). We know that Bing users are usually older, more US-based and more likely to have children, all implying that they are more likely to be spending consumer dollars.If this is the demographic you’re targeting, then consider optimizing for Bing instead of Google. Here’s a handy cheat sheet to get you started. Most of the rules are similar to SEO for Google, with some tweaks. Although some ideas — such as having a keyword-rich domain name — seem curious. (As any journalist will tell you after their first day, whitehouse.com is not keyword-friendly content; it’s porn. Eventually, we find our way to whitehouse.gov.)