Yes you can. It allows you to create customer groups for your store. Customer roles allow you to group your customers. A customer can be a member of more than one role and a role can have many customers. Roles allow you to apply benefits such as free shipping and tax exemption to a group.
 

You can add new Role and can also create a discount promotion and assign this to a customer role (go to Promotions => Discounts to manage discounts).
 

To add a Customer Role:

 

This is a method by which you can offer a different pricing structure and discounts to your customers based on which customer group they belong to. A common example of customer groups is a retail/wholesale type of set up, where regular customers are able to purchase your products at the regular price, but special customers are able to purchase your products at wholesale prices, provided they belong to that special pricing group. Another example may be you divide customers on bases of region and offer special discounts etc.