As marketers plan their holiday campaigns, a WebVisible report suggests that small businesses are spending more on search advertising this year compared to 2009. Ad spend may be growing, but the study indicates it is showing signs of leveling off and that marketers are leaning toward Bing.

In a survey of more than 12,000 small businesses, WebVisible’s Q3 2010 study found that advertisers increased their spending by 6.4 percent over Q2 2010 and by 43 percent over the same period last year. While this is substantial growth, it demonstrates a drop from the year-over-year spending increases of 90 percent or more during the first half of 2010.

WebVisible thinks the slowing spend may be due to the fact that marketers are learning how to most efficiently spend their advertising dollars. The climbing keyword count per advertiser (up 41 percent over Q3 2009) also indicates that SMBS are improving their campaigns and getting more competitive with respect to paid search.

It seems that businesses are increasingly looking to become competitive on search engines other than Google. During Q3 2010, marketers boosted their investments in Bing, according to WebVisible. Microsoft’s search portal gained 3.7 percentage points of search spend share quarter-over-quarter and 4 points year-over year. Meanwhile, Google’s share of search marketing spend dropped 5.8 points over the previous quarter and 8 points over Q3 2009.

The firm expects Bing to account for 40 percent of small business ad spend in light of the Yahoo/Microsoft paid search transition taking place, reported by Brafton earlier this month. Notably, the rising ad spend on Bing seems to meet consumers’ demand, as comScore says Bing and Yahoo now account for nearly one-third of total core searches.

With this in mind, marketers may want to prepare their paid search spend for Bing during Q4 2010 accordingly. Those who act fast can get their campaigns in order in time for “Peak Week” during early December, which Brafton reports provides the highest ROI for paid search campaigns throughout the holiday season.