Facebook has partnered with several retailers as well as Zendesk, a customer-service platform, to let you talk with companies like you would in a normal message thread.
When you buy something from Everlane, for example, and have your Facebook account tied into the order, your order details get sent to you in Messenger. You can request shipping status updates and get customer support directly in the app.
Facebook is starting to integrate more businesses into Messenger, but for now, this experience only works with Everlane and Zulily for retail.
If you're interested, read more about our experience of talking to Everlane in Messenger.