LinkedIn, the social-networking website for professionals, said it reached 100 million members Tuesday, as it gears up for its much-anticipated IPO.The company filed for its IPO with the SEC on January 27th, and it usually takes about 2 months for the SEC to complete its review.The website was founded in May of 2003, and had 71.5 million unique visitors in February 2011, up 55% from February 2010, according to comScore.Over half of LinkedIn’s users, 56 million, are based outside the United States. Last year, membership grew 428% in Brazil, 178% in Mexico, 76% in India, and 72% in France, highlighting its truly global appeal.LinkedIn hired Morgan Stanley (NYSE:MS), Bank of America (NYSE:BAC) and J.P. Morgan Chase (NYSE:JPM) to lead the offering, according to the SEC filing.