What are the security problems related to adware?

What will be an ideal response?

Beyond being a nuisance, adware can also be a security risk.Many adware programs perform a tracking function,which monitors and tracks a user's activities and then sends a log of these activities to third parties without the user's authorization or knowledge. For example, a user who visits online automobile sites to view specific types of cars can be tracked by adware and classified as someone interested in buying a new car. Based on the order of the sites visited and the types of Web sites, the adware can also determine whether the user's behavior suggests they are close to making a purchase or are also looking at competitor's cars. This information is gathered and then sold to automobile advertisers,who send the users pop-up ads about their cars.