Domain Validated certificates are certificates that are checked against domain registry. There is no identifying organizational information for these certificates and thus should never be used for commercial purposes. It is the cheapest type of certificate to get, but this is a high risk certificate.
Organizational certificates are trusted and strictly authenticated by real agents against business registry databases hosted by governments. Documents may exchange and personnel may be contacted during validation to prove the right of use. OV certificates therefore contain legitimate business information.
EV certificates reinstate the trust users have for a secured web site. The criteria for issuing EV certificates are defined by the Guidelines for Extended Validation and provide a vetting process that is much stricter than that for OV certificates. Apart from improving trust and confidence via the strictest authentication process.