Here is the test: Does the software do anything that I want it to do? Did I install it or did I have a choice in installing it (a real choice, not a tricky dialog box). And finally, the true test... if someone UNINSTALLED or stopped this software from functioning, would I actively try to re-enable it.
If it doesn't meet these criteria, then it is spyware, crapware, malware, or junk, and should be classified as malicious. This includes almost all programs and web pages. This is Sturgeon's law, 90% of everything is crap. But in computer science you can take it one step farther. 90% of everything is crap, and 90% of the stuff that is worthwhile is designed to keep away the crap.