Few startups need gear as much as Facebook. Begun in 2004 by Mark Zuckerberg, Facebook is growing rapidly. In March, Facebook attracted just over 35 million users in the U.S., up 71% from nearly 21 million a year earlier, according to comScore (SCOR). Its worldwide total more than tripled to 109.2 million in the period, according to comScore. International expansion continues apace. Facebook recently launched sites in Spain and Germany, as well as a French-language site.