The website crawls the Internet for publicly accessible devices, concentrating on SCADA (supervisory control and data acquisition) systems.  Shodan currently returns 10 results to users without an account and 50 to those with one. If users want to remove the restriction, they are required to provide a reason and pay a fee.  The primary users of Shodan are cybersecurity professionals, researchers and law enforcement agencies. While cybercriminals can also use the website, some typically have access to botnets that could accomplish the same task without detection.