Online social network for job seekers and professionals LinkedIn, registers its 100 millionth member and it is now growing at a rate of roughly one million new members every week. On March 11, in a regulatory filing, the new total is about 10 million more than LinkedIn disclosed. LinkedIn Chief Executive Jeff Weiner wrote in a blog post that Brazil and Mexico are among it's fastest growing countries. LinkedIn is seeking to raise up to $175 million in an initial public offering hoping to capitalize on the frenzied interest in privately held Internet companies such as Facebook, Twitter and Groupon. While LinkedIn's membership is growing, the company said in a regulatory filing for its IPO in January that a “substantial majority” of its members do not visit the site on a monthly basis.