Nuisance e-mails, commonly known as SPAM, are unsolicited messages sent to a large number of recipients. These messages are usually advertisements or other forms of marketing, and can be extremely annoying for the recipient. They can also contain malicious content such as viruses, malware, and phishing scams. Nuisance e-mails are a major problem for internet users, and many organizations have implemented measures to protect their users from them.