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Americans turned to the web in March 2009 to plan spring and summer travel and manage their personal finances, but also flocked online to feed their growing obsession with microblogging site Twitter, according to the monthly analysis of US online activity from comScore's Media Metrix service (via MarketingCharts).

Growing Twitter Frenzy

After months of double-digit growth, traffic to Twitter.com accelerated in March, growing 131% to 9.3 million visitors, comScore said.

Fueled in part by attention from mainstream and online media and celebrity "tweeters," the site ranked as the top-gaining property for the month.

"March represented an especially big gain for [Twitter] as it added more than 5 million visitors versus the previous month," said Jack Flanagan, executive VP of comScore Media Metrix. "With numerous celebrities and media personalities - including Oprah - recently jumping on the Twitter bandwagon, the site shows no signs of slowing."

Americans Seek Financial Advice Online

During March, many Americans also sought financial advice online to help navigate the turbulent economy, resulting in a 12% gain at the Financial Information/Advice category. Most notably:

• Consumer concerns about the status of their credit rating drove traffic to FreeCreditReport.com, which grew 6%to 6.6 million visitors and ranked as the most visited site in the category.
• Bankrate.com Sites, which provides rate information on various financial products such as mortgages, credit cards and money market accounts, reported a 12% increase to 3.9 million visitors.

Travelers Plan Summer Trips

As Americans prepare for spring travel and summer vacations, several travel categories witnessed gains in March, comScore reported. Travel - Transactions led as the top-gaining category for the month, growing 18 % to 4.5 million visitors.

The Car Rental and Airlines categories also saw double-digit gains, each growing 11% to 5.6 million and 29.8 million visitors, respectively. Southwest Airlines Co. led the Airlines category with 11.3 million visitors, up 20% from the previous month, followed by Delta Airlines with 6.5 million visitors (up 5%) and American Airlines with 5.8 million visitors (up 25%).

Google Still atop Top 50 Properties

Google Sites continued to lead as the most visited property in March, with more than 151 million visitors, comScore said. Google is followed by Yahoo! Sites with 146 million visitors and Microsoft Sites with 122.3 million visitors.

Also notable: Facebook.com moved up one spot in the ranking to #9 this month with 61.2 million visitors.

Platform-A atop Top 50 Ad Focus Ranking

Platform-A led the March Ad Focus ranking, reaching 90% of the 192 million Americans online. Yahoo! Network ranked second, reaching 86%, while Google Ad Network moved up one spot to #3 with an 84% reach.