Adware in the purest sense of the word is not a dangerous thing, designed only to display targeted advertising to you while browsing the internet. It was originally developed by marketers to be non intrusive and use very little system resources. You can easily recognize adware by the display of pop up advertisements on your computer screen, often appearing when you perform searches or land on different websites.
Adware can be very annoying, and in the past few years much of adware's functional characteristics have begun to resemble spyware. A large percentage of adware today includes code that tells the advertiser something about you. It often relays information about which sites you visit on the internet, how much time you spend on each site, and what type of content you viewed. Although marketing people consider this information to be harmless to you, most users consider this type of data gathering to be an invasion of privacy. Adware that is delivered in the form of email often tells marketers when you opened the mail, how long you looked at it, and what you did with it.
