Amazon\, With Little Fanfare\, Emerges as an Advertising Giant

Amazon, With Little Fanfare, Emerges as an Advertising Giant

Its push challenges the big ad sellers, including Facebook, Google and TV networks

Amazon wants to deliver everything you want to your doorstep, anywhere in the world. But the e-commerce giant faces several challenges in its pursuit of a global empire. WSJ's Karan Deep Singh breaks down the basics with the help of an Amazon delivery box.

Amazon.com Inc. handles nearly half of all online sales in the U.S., giving it a popular platform and a wealth of consumer data. Now it’s on track to become the next juggernaut of online advertising, and its rise threatens to upend Silicon Valley’s ad titans and change the way business is done on Madison Avenue.

The online retailer has ascended to the No. 3 spot in the U.S. digital ad market behind the dominant players, Alphabet Inc.’s Google and Facebook Inc. Though Amazon has just 4% of the market now, the company is expanding...