Ad giant Omnicom Group has signed a $100-million advertising deal with social network Instagram to promote new publicity formats and boost participation of both users and advertisers.The contract comes only months after Instagram began displaying ads and being tried out by brands such as Michael Kors and Ben & Jerry’s. Omnicom is one of the biggest advertising groups in the world, with a host of big-name clients like Procter & Gamble and General Electric. Instagram, acquired by Facebook for almost $1 billion in 2012, boasts more than 150 million users.”[The Omnicom deal] doesnt change our advertising strategy moving forwardpeople will continue to see a limited number of beautiful, high-quality photos and videos from select brands that already have a strong presence on Instagram,” said Jim Squires, Instagram’s director of market operations, in a statement to Ad Age, while Daryl Simm, CEO of Omnicom Media Group, described the partnership as another example of the media becoming the message.”Ads will come in the form of photos or videos, which will be posted in the feed for more than a day. Both companies say that users will not be flooded with too many ads night and day, which could put them off, but rather that Instagram will try to control the experience as much as possible.