Twitter is more popular than Britney

Twitter keeps growing faster each day… Comscore just released its March metrics and estimates that Twitter grew 131% since February to 9.3 million viewers. To give a sense of the type of growth, here is the month-to-month growth in U.S. unique visitors so far this year:

March, 2009: 131%
February, 2009: 55%
January, 2009: 33%

It’s so popular that “Twitter” surpassed “Britney” a few months ago and is even slightly ahead of “Obama” according to Google Trends.