In a new blog post, WhatsApp has announced that a greeen badge will appear next to to a contact's name, designating that WhatsApp has confirmed the contact's phone number as belongsingto a business account. Although it's still on in at the pilot stage, the program will allow you to block calls and messages from businesses as well as giving you confidence that the person contacting you is from a legitimate business.
With the number of contact channels businesses can use expanding, being able to prove who you are is important. Threat actors often rely on people handing over information to supposedly trustworthy parties. This sort of validation, which seems to be similar to Twitter's identity verification process, will help give you more confidence.
The post, on the WhatsApp FAQ says WhatsApp will let you know when you start talking to a business via yellow messages inside a chat. If you already have a business's phone number saved in your address book, the name you will see is the name you have saved in your address book.
In the long term, it seems WhatsApp's owner, Facebook, is following their tried and true business model of building market share first by delivering features and then looking for ways to generate revenue. How this will work for WhatsApp is unclear but it's possible the service will offer a premium service for business users.