Today LinkedIn, the most popular professional social network, has reached the mark of 100 million members worldwide, according to its own advertising tool. It’s growth rate is increasing: in october 2009 user base was 50 million, in May 2010 jumped to 70 million. 56% of users are outside United States. Top countries are: U.S.A., India, U.K and Brazil. Among European countries the most active are: The Netherlands, France and Italy. 61% of members are men. Both users between 25-34 and 35-54 years old are 36%, while 18-24 years old are 21%. The most represented industries are hi-tech (17%), finance (14%) and manufacturing (10%), while sales (12%), academics (10%), administrative (10%) are the most common job functions.