Similar to antivirus programs, anti-spyware programs help to block and prevent spyware and other malware infections on computers. Anti-spyware programs monitor incoming data from e-mail, websites, and downloads of files and stop spyware programs from getting a foothold in the computer operating system. They are also frequently updated by the developer, to keep it up-to-date and able to block the most recent spyware programs known to exist.
Some anti-spyware programs are designed only to block spyware, while others prevent both viruses and spyware. Lavasoft's Adaware SE, Malwarebytes, and Spybot - Search & Destroy are programs designed to target spyware only. McAfee, Symantec, Kaspersky, and Webroot all designed their software to block both viruses and spyware. For safety, it's best to purchase an anti-spyware program from a retail store or a well-known online retailer, to ensure you are getting a legitimate program. There are some supposed anti-spyware programs available to download on the Internet, but some are actual spyware programs in disguise and will ultimately infect your computer.