• by Laurie Sullivan  @lauriesullivan, May 12, 2014

ABC, Expedia, GAP, General Mills, Target and other major brands are working with Pinterest to roll out Promoted Pins in the search category feeds on Pinterest.

Hui Xu, head of the discovery team at Pinterest, estimates about 750 million boards on the site with 30 billion pins about travelers, foodies, and more.

With all the possible options, brand marketers have had to become mindreaders to predict phrases that consumers will use to search for their products and services. Last month, Pinterest introduced Guided Search. The feature suggests other category topics based on the initial search query. Dog food might suggest dog trainer, dog collars or dog toys. It is intended to bring up common things that people search for along with items related to the original phrase or topic.

Native ads have become the new paid-search ad unit that combines images and text to create an ad unit brand marketers call "content." Yahoo also announced Monday a update to its native ad format available through Yahoo Gemini. The ad unit, which runs on mobile devices, supports larger graphics and photos and makes it easier for brands to tell their story. The sponsored ads appearing in the news stream look and act similar to the content around them, so visitors can tap on the ad to click through to the brand's landing page or Web site. Netflix, among others, uses the new ad formats.

Overall, digital advertising in the U.S. should reach $50.11 billion in 2014, per eMarketer. Retailers will account for $11.05 billion, or 22.1% of the total this year, while consumer product goods and travel categories will each account for around 8% of all U.S. digital ad spending.

As for Pinterest, there were 34.9 million U.S. users accessing the site at least once monthly in 2013, per eMarketer. The analyst firm expects 15.9% growth in 2014 to about 40.1 million. A majority of users are female -- some 30 million in 2013, compared with 4.9 million male Pinterest users. More than two-thirds of Pinterest users in 2013 were between the ages of 18 and 44.

Similar to other social sites, Pinterest claims that a majority of its traffic now comes from mobile devices. In the U.S., eMarketer expects mobile advertising to rise 83% to $17.73 billion this year, up from $9.69 billion in 2013.