New York—Internet services company AOL Inc. has reached an agreement to acquire video advertising technology company Adap.tv for $405 million in cash and stock. Adap.tv, based in San Mateo, Calif., operates a programmatic (real-time bidding) ad-buying platform, offering automated tools to plan, buy and measure digital video ads. According to a report last month by comScore, Adap.tv served 2.2 billion video ad impressions in June, behind Google sites' 3.3 billion. Along with the rise of programmatic media buying, digital video ad spending also is growing rapidly. According to eMarketer, marketers will spend $4.1 billion on digital video ads in the U.S. this year, up 41% from 2012.