There are many benefits of social media websites like Facebook, Twitter, Pinterest etc.
1. People come to know about your business.
2. Products you sell.
3. Quality of your products.
4. Discount on products
5. You can do any kind of promotion to increase your business on social media websites.
6. Contests : Tell People to participate in contests and give gifts to winners . This way, You can promote your business.
Hope this will be helpful. Cheers.