For years, Wal-Mart Stores Inc. has followed Amazon.com Inc., putting inventory online and starting its own version of a marketplace where third-party merchants can sell their wares. Now Amazon is returning the favor.
The e-commerce behemoth is building pickup locations for groceries in Seattle that could open by the end of the year, according to someone familiar with the plans, echoing a strategy embraced by its chief brick-and-mortar rival.
