Centro was created to streamline online media buying and planning for ad agencies and publishers . In 2008 , Centro helped 213 agencies develop and execute successful online advertising on behalf of 456 advertisers and currently has more than 10,000 media companies indexed in Transis , its proprietary software . With just over 100 employees , Centro continues to experience growth after the 1,433 % growth rate from 2004 to 2008 .