"Spikes in these categories are a clear indication that consumers are preparing to enjoy warmer weather and beginning to plan for holiday, spring and summer vacations," said Peter Daboll, comScore's CEO. "Additionally, this month shows undeniable growth within the online classifieds category, which grew an impressive 35 percent from last year, and 13 percent versus last month. Notably, properties such as Craigslist.org have exploded since last year (up 155 percent since March 2005), an indication that online classifieds continue to draw attention from their print counterparts."

In addition, many consumers logged onto travel-related Web sites in March to make plans for holiday, spring break or summer trips, comScore said. More than 6.8 million Americans visited car rental Web sites, up 22 percent from February. Nearly 10 million consumers clicked on to ground transportation and cruise Web sites, up 17 percent over February, while 32.9 million visited hotel and resort sites, an increase of 13 percent for the same period.

Traffic to online training and education sites also soared during March, according to comScore. Overall, the training and education category rose 22 percent over February. Visits to CollegeBoard.com, the official SAT Web site, were up 14 percent to 2.8 million visitors, while traffic to PrincetonReview.com increased by 39 percent to 693,000 visitors. And Fastweb.com, a site offering college scholarships, had 1.7 million visitors, up 35 percent from February, comScore said.

March was also a strong month for online classifieds, which grew 13 percent over February and 35 percent year over year, comScore said. Craigslist.org was the most visited online classified site, with 9.5 million visitors, up 12 percent since last month, and up 155 percent since March 2005. In addition, 8.3 million visitors logged onto the Web site of Trader Publishing Co., publisher of Auto Trader magazines, an increase of 10 percent over February, while 4.2 million people visited Cars.com, up 28 percent from February. In its monthly analysis of competitive search engines, comScore said Americans performed 6.4 billion online searches in March, up 10 percent from the previous month and 15 percent from March 2005. The increase in search queries from the previous month was the largest gain over the past 12 months, comScore said.

For the eighth consecutive month, Google gained in search market share compared with a year ago and maintained its status as the market leader, with 42.7 percent of searches conducted on its sites. Yahoo remained in second place, with 28 percent, while Microsoft Corp.'s MSN ranked third, with 13.2 percent.