U.S. paid search made solid gains in 2010 with 18.5 percent growth year-over-year, according to a new report from SearchIgnite.

The fourth quarter (Q4) showed strong growth, increasing 35.5 percent YoY with December leading the quarter at 44.8 percent YoY growth. The Q4 holiday season indicated improved consumer sentiment, with the average order value (AOV) up 31.3 percent YoY compared to a 13 percent decrease in 2009.

“2010 proved to be a great year for search advertising as the search market recovered from the downturn,” said Roger Barnette, CEO of SearchIgnite.

“Even more promising is the revival of consumer spend throughout the year and the strength of Average Order Values in Q4. We expect 2011 to be a strong year for search and online advertising overall.”

Other findings in the report include:

*Retail saw significant increases in search spend in Q4 (up 36.6% YoY)

*All other underlying metrics in Q4 show positive results with 20.6% YoY increase in clicks, 2.3% YoY increase in impressions and 17.9% YoY increase in click-through rates.

*Google’s share of advertising spend in Q4 increased to 82.6%, up from 80.2% in Q3. Yahoo/Bing accounted for 17.4% of Q4 spend.