SUNNYVALE, California: Search adspend among some of the biggest advertisers in the US fell by 13% year-on-year in the first quarter of 2009, reports Efficient Frontier, the search engine marketing firm.

Based on an analysis of data from its own clients, which include a number of major marketers, and who produced 84 billion online impressions and 785 million "clicks" in Q1, the company also found that search spend was down 3.3% quarter-on-quarter.

Google retained its dominant position with a 72.3% market share in the first quarter, down just 0.9% year-on-year, with Yahoo up 1% to 19.3%, and Microsoft falling a similar amount to 3.5%.

Efficient Frontier also reported that Google's overall content network saw clickthrough rates rise 250% on an annual basis, and its market share on this measure rose 1.1% to 4.8% in all.

Overall impressions rose 11% in the first three months of this year despite the drop in spending, a sign that "more people are searching online and that search engines are optimizing unused inventory."

Total impressions rose by 20% on Google's search portal, with Microsoft Live Search up 10%, with these two firms also seeing an uplift of 10% and 43% in ROI respectively in Q1.

Yahoo's return on investment was also up 12%, part of a broader trend that advertisers are "shifting towards efficiency in their marketing campaigns."

With regard to specific categories, the financial sector cut back on spending but still posted an upturn in the number of impressions.

Retail enjoyed a greater number of searches, but advertisers are also seeing their budgets fall, while a decline in clickthroughs also seemed to indicate that "more searches in the retail space are from comparison shoppers, not serious buyers."

Automotive firms cut their search outlay by 7% year-on-year, with traffic falling by 32% on an annual basis, though clickthrough rates rose 36%, showing that consumers viewing ads were on target.

Efficient Frontier also warned that its figures do not necessarily indicate how companies like Google are performing overall.

This is because it tracks the search spend of a consistent group of companies over time, while figures from search firms include new advertisers, and a broad range of smaller companies not picked up by Efficient Frontier's analysis.

Data sourced from Efficient Frontier/Wall Street Journal; additional content by WARC staff