By BRAD STONE
Published: NYT March 28, 2009
WHEN Facebook signed up its 100 millionth member last August, its employees spread out in two parks in Palo Alto, Calif., for a huge barbecue. Sometime this week, this five-year-old start-up, born in a dorm room at Harvard, expects to register its 200 millionth user.
That staggering growth rate — doubling in size in just eight months — suggests Facebook is rapidly becoming the Web’s dominant social ecosystem and an essential personal and business networking tool in much of the wired world. .........