The Better Business Bureau is a non-profit agency that attempts to further good business practices.  Companies can get accredited which means they pay a fee and agree to certain standards.  BBB has no power to punish or sanction anyone other than take away the accreditation of the companies that register.  

However, the BBB does publicize complaints on its website and their company information site is quite helpful.  It lets people know about repetitive complaints and deceptive practices.  The company engaged in fraud which professes surprise at a complaint will be undermined upon seeing 5 or 10 complaints by other consumers. 

1. Ratings 

Their rating system is quite easy, a company with multiple complaint engaged in deception can get an A.  The penalties come with a failure to respond, but many companies will provide false or misleading responses.