There are 3 different levels of vetting that SSL Certificates are based upon. Domain Validated (DV) , Organization Validated (OV), and Extended Validation (EV). The major difference between the types of certificate relates to the information the Certificate Authority, RapidSSL, GeoTrust and Comodo, requires and validates in order to issue a certificate. The higher levels of certificate require more information, and often is displayed in the browser bar. EV SSL for example turns the browser bar green and displays the organization name to visitors to generate more trust.