Forbes: Ever since it bought the display-ad serving system DoubleClick in 2007, Google has been steadily buying up more pieces of the online ad-buying process beyond its core search ads. But it has had one huge hole: social ads. With the rise of advertising on Facebook and Twitter, Google has been left completely out of the picture when it comes to offering marketers a way to get in front of people when they’re on social networks and use data on what they’re doing there to improve the relevance of its ads.
