Search spending demonstrated 17 percent annual growth in 2011, according to a study from Efficient Frontier relayed by Search Engine Land. Interestingly, Efficient Frontier says its clients are seeing greater return on investment (ROI) from Bing, so marketers may want to optimize for Microsoft's search portal.

The agency found that the rise in search spend was matched by year-over-year increases in click volumes. The retail and financial sectors seemed to drive the growth. Marketers in the retail industry spent 22 percent more on search in Q1 2011 than during the same period last year, and this was rewarded with more engagement in the form of 30 percent year-over-year gains in impressions. Finance marketers saw a 22 percent increase in clicks.

While ROI remained steady overall, Efficient Frontier's clients saw more ROI on Bing. Bing's ROI has grown 10 percent since Q1 2010, and Google's ROI has decreased by 12 percent. ROI on Bing is reportedly 12 percent higher than on Google for the agency's clients, and this may inspire marketers to optimize their sites for Bing. (For more, see Brafton's blog on how to boost Bing SEO.)

Nonetheless, Google holds the dominant market share in terms of search spend and clicks, and Search Engine Land reports that Efficient Frontier expects Bing ROI will not be sustained when the Bing-Yahoo network is expanded.

Whether choosing to optimize for Bing or Google, the data suggests that businesses need to invest in search marketing to maintain a competitive edge this year. Efficient Frontier's search spend analysis confirms its earlier prediction that spend would continue to rise following strong growth in 2010, and brands might consider SEO a marketing must.