Dive summary: 

• The Federal Trade Commission has opened yet another investigation into Google; this time to see if the firm abuses its market-leader position to curb competition in display advertising. 
• The investigation will center around whether Google's DoubleClick ad network and its buying tools forces brands to purchase their other products versus trying competitors like Yahoo or Microsoft. 
• This follows an investigation concluded five months ago in which the FTC looked into whether or not Google unfairly manipulated its search results.

From the article: 

"Google reported $2.26 billion in display ad revenue in the U.S. last year, a figure that is projected to hit $3.11 billion this year, according to eMarketer. Google's 15 percent share of the market bests Facebook (14.5 percent), Yahoo (9 percent), Microsoft (4.5 percent) and AOL (3.5 percent)."