Why is DMARC so important?

With the advent of the social internet and the ubiquity of e-commerce, spammers and phishers have an enormous financial incentive to compromise user accounts and enable the theft of passwords, bank accounts, credit cards and various valuable data. Emails are easy to forge, and criminals have discovered that spoofing is a proven way to exploit the trust of users of well-known brands. By simply inserting the logo of a well-known brand in an email, this is immediately legitimized for many users.