In March, Walmart announced that it would begin delivering groceries to 100 new cities this year, up from the six it serviced at the time. Since then, it's announced partnerships with Postmates, and now, DoorDash, to make that promise a reality.

What does DoorDash have to gain? Data, according to our sister publication. The service's drivers are typically busy later at night, this would give them something to do during non-peak hours. The extra data would then help DoorDash become more efficient and open the door to delivering more than just food.