Facebook owned messenger app WhatsApp announced in a FAQ on it’s site that, it is exploring way for the user to contact with businesses. A very small number of businesses has been verified by WhatsApp and given a green tick badge next to their name.
Since, the project is in pilot phase, very small number of businesses who participated in the project are given the verified badge. If you see some of your contact with green badge that means it is a business account and verified by WhatsApp.
WhatsApp will also let you know when you start talking to a business via yellow messages inside a chat. There is no way to delete these messages from the chat.
If you have some of your contacts number as business account, you can see the name as you saved it in your contact but If you don’t have a business’s phone number saved in your address book, the name you will see is the name the business has chosen for themselves.
If you’d like to stop a business from contacting you, you can block them.
Also read interesting story about Facebook