Sridhar Ramaswamy, who helped build Google's ad business into a money-machine, is leaving to join a venture capital firm. He will join Greylock Partners as a venture partner. He started at Google's Ad groups in 2003 was generating $1.5 billion. In 2013, the company recorded ad revenue of $95 billion. Ramaswamy will be replaced by Prabhakar Raghavan, vice president of Engineering at Google. Sridhar Ramaswamy, one of the people responsible for Google’s success in advertising, is leaving the company after 15 years to become a venture capitalist, according to reports.