Five criteria for determining spyware

Here are the five criteria that Microsoft (and others) use to determine if a program qualifies as spyware, and the level of danger that it poses.
1. “Deceptive behaviors. Runs processes or programs on the user’s computer without notifying the user and getting the user’s consent. Prevents users from controlling the actions taken by the program while it runs on the computer. Prevents users from uninstalling or removing the program.”

2. “Privacy. Collects, uses, or communicates the user’s personal information and behaviors (such as Web browsing habits) without explicit consent.”

3.”Security. Attempts to circumvent or disable the security features on the user’s computer, or otherwise compromises the computer’s security.”

4. “Performance. Undermines performance, reliability, and quality of the user’s computing experience with slow computer speed, reduced productivity, or corruption of the operating system.”

5. “Industry and consumer opinion. Considers the input from software industry and individual users as a key factor to help identify new behaviors and programs that might present risks to the user’s computing experience.”

You can go here to read more about it, including longer explanations of the five criteria. You will find them about halfway down the page.