Amazon.com Inc.’s move into digital advertising so far has mostly come at the expense of market leader Google since shoppers often bypass the search giant and look for products directly on Amazon.com. Now, the world’s largest online retailer is starting to grab advertisers from Facebook Inc., too.
For years, Facebook — No. 2 in U.S. digital ad sales — was largely immune from such encroachments because social-media sites were considered distinct from the search advertising prominent on Amazon and Alphabet Inc.’s Google. Then in June Apple Inc. intoduced privacy changes on iPhones that made Facebook advertising less effective.