What is (website) malware?
You probably already know the word “malware” from PC’s and computers. Computer viruses have been around a long time, as well as virus scanning software. With the Internet age came “spyware” (programs that spy on what you do and send the details to a remove computer), as well as “anti-spyware” computer software. You might also have hard about trojans, and key-logging software as types of computer virii. The term “malware” in conjunction with a computer means something installed on your PC in order to deliver a payload. Like installing a browser toolbar, and having it (on the backend) install a script, program, or trojan without your knowledge as the payload.
Google started tracking malware in websites a few years back as part of Google webmaster tools. Malware (at that time) was known mostly as something installed in your website designed to deliver a payload unknowingly to the website visitor (also like a virus, trojan, program, script, etc.). Now, the term is used to cover nearly any compromised website wither it delivers an actual payload, redirects the user to a rogue website, or may contain some spam.