• by Laurie Sullivan , Staff Writer @lauriesullivan, June 29, 2010

Travel-related Web sites gained insights into the 2010 travel season Tuesday. Google released a whitepaper providing highlights of search query behavior in 2009 to help advertisers plan for this year's summer excursions. The research, "A Paper of Two Halves," details query and click growth, explains why CPCs have fallen, what impact the World Cup had on search, and changes in this year's search seasonality. The report was released by the Google travel team in the U.K.

Travel queries rose 20% this year, compared with last year. Air-related queries jumped 24% and clicks on travel ads are up 13%. Jonathan Cranmer, Google industry analyst, explains in the whitepaper why query and click growth continues to accelerate this year. He suggests understanding the dynamics and changing volumes of keywords and product demands and attributing value to generate keywords throughout the purchase funnel will help marketers exploit conversion rates and lifts in query volumes.

Strong query growth in April occurred due to the ash cloud from the volcano, which closed U.K. air space from April 15-22. During this time, search queries about air travel rose 47%.

For the first five months in 2010, CPCs for travel ads fell by an average of 4%, compared with the prior year. Car and hotel CPCs fell by the greatest amount, 7% on average.

You know what that means. Cranmer explains ads have become more affordable, compared with last year. More affordable means marketers can increase bids to drive greater volume to Web sites. The whitepaper suggests using the cheaper CPCs to your advantage. Adopt an "always on" policy to leverage cost effective traffic.

Data also shows the World Cup had an impact on search volume. In 2006, queries dropped by 6% during the World Cup, before strong growth the following month to compensate. On Monday, Google released data on last week's most popular World Cup-related searches. The data collected ahead of matches played by the last 16 teams in the tournament shows searches for 'world cup standings' rose steadily.

Experian Hitwise also released search data. U.S. searches on Portugal star soccer player Cristiano Ronaldo accounted for one-fifth of all World Cup player searches last week in the United States. Ronaldo received 19.16% of all U.S. searches, and was the top searched-for player in France, Brazil, Australia and New Zealand markets and number four in the United Kingdom.