SILICON VALLEY -- Social networking sites Twitter and Facebook again posted big numbers in March.
Traffic at Twitter grew nearly 77 percent between February and March, as millions of Americans logged onto the quirky microblogging site for the very first time.
Industry analyst Compete.com estimates 14 million Americans visited Twitter last month.
Meanwhile, Facebook saw its own surge, growing an impressive 23.3 percent itself, reaching 91 million Americans.
2008 was a big year for Facebook, which has seen its traffic jump 200 percent in the past 12 months.
Analysts say the new traffic at Facebook and Twitter is due, in part, to reporters talking and writing about Facebook and Twitter.
SILICON VALLEY -- Social networking sites 
