Unsolicited and mass-sent e-mail. These account for more than 85% of the total e-mail volume and hinder productive communication via e-mail.

Depending on the purpose of the spam email, a distinction is made between different types:

• Unsolicited commercial e-mail (UCE)
• Phishing
• Scareware
• CEO Fraud

Email filters help against spam. An e-mail that is falsely marked as spam is called a “false positive”.