They seldom contain an unsubscribe link, and if it does, that link may be embedded with malware.

These emails often use scare tactics, contain typos and misleading information, and are sent in bulk from an anonymous sender. Spam messages often come from illegitimate email addresses, and may contain explicit or illegal content. They allow you to subscribe to a newsletter, sign up for services, read members-only content, or share messages via email and social media. Generally, legitimate marketing emails are sent by businesses once you opt in to receive them.

But there’s one difference between a spam message and marketing message: permission. You probably receive email spam and marketing messages regularly. Spam emails, otherwise known as junk mail, are uninvited bulk-sent email messages delivered to an inbox.