Unwanted e-mail, also known as SPAM, is a type of electronic communication that is sent without the recipient's consent. It is usually sent in bulk and often contains advertisements or other unwanted content. SPAM can be a nuisance to users, as it can clog up their inboxes and take up valuable storage space. It can also be dangerous, as it can contain malicious links or viruses. To protect against SPAM, users should use anti-spam software and be careful when clicking on links in emails.