The recipients can send spam complaints in three ways:
- By using a link or button like "Report Spam" provided by large ISPs such as AOL, Yahoo!, Hotmail, EarthLink, NetZero, and Juno.
- By using a spam complaint service such as SpamCop or Vipul’s Razor.
- By sending spam complaints directly to e-mail abuse addresses at ISPs and the FTC.
ISPs and anti-spam services use spam complaints to improve their anti-spam algorithms. They also use complaints as a sort of voting system to decide whether the email coming from a certain IP address is good or spam. Too many complaints may cause a message being filtered into junk folders or rejected entirely. The sender then may be required to take specific steps, such as reconfirming a mailing list, before he is allowed to send the emails again.