Scanners and firewalls. Get a good virus scanner, which checks all of the files on a computer to see if there are viruses, and be careful of what you download and run on your computer. Personal firewall software will help to protect you when you are surfing the Internet. Exercise common sense. Take time to read and understand the privacy policies of any web site you give information to.
Many sites collect and disseminate information.
A reputable site will publish their privacy policies.