Retailers are trying to make smartphones work for them instead of against them. Take Maurices. The women’s clothing chain last month started sending promotions to the phones of people who come within a few hundred yards of its stores. Consumers who opt in to the service are sent messages about in-store sales. There is little evidence that sort of marketing actually works, but Maurices wants to give it a shot, in hopes of drawing people to the chain’s bricks and mortar locations.