Spam has become a daily nuisance for everybody. The number of spam e-mails can overwhelm our inboxes, reducing the space and chances for important messages to be received. Besides, they are a constant and real threat to our security. Scams, phishing attacks, malware can be attached to them, risking our personal information, business, and systems.
Fortunately, developers constantly improve and innovate with tools to defeat, or at least mitigate, these threats. DKIM is an example.