Spyware is a term used for software that spies on your computer and your computer habits. Spyware is a major threat to a computers user and the network it’s connected to. In some cases, spyware will be installed on your computer as a bundle from a trusted program. For example, popular torrent software uTorrent is known to install spyware on your computer as part of its own install.
The end goal for spyware is theft. Sometimes it could be as simple as an e-mail address or contact list to be on-sold to e-mail scammers, other times, it could result in your bank account being accessed to withdraw money. Identity theft is possibly the biggest area of concern with spyware, with people storing so much information about themselves on their computer, a hacker can use all the information gathered to steal your identity for use anywhere.
Best practice to avoid spyware is regular computer maintenance and scans with multiple and reputable software. Spyware is designed to hide, so it may not be a simple fix.