Adware has its Pros and Cons, sure you get to use a program for free but with adware there can be associated spyware. So what is the difference?
As mentioned earlier adware is just where you get ads in exchange for using the software, whereas spyware is where a code or program is inserted without your permission which tracks the user and passes personal information on to the owner about the user, the owner of the program may use this information personally or they may sell the information to another party who is able to use it and take advantage of the information in many ways but usually it is by marketing. All this information about you is being passed around without your permission and probably without your knowledge.
This practice is actually information theft, and may be unethical but at the moment it is not illegal because so far there is no way to regulate this kind of practice. If someone stole your car, most likely you would be pretty upset about it, do we tolerate people stealing information about us. To a certain degree we do but it is only because we don’t understand the implications of the theft.
I’m sure that when adware first came about it was innocent enough with the software programmers wanting people to experience the program and then make a donation or at least support them by viewing the sponsors advertisements, but maybe they weren’t getting enough and a better plan came along. Lets actually find out what they want by spying. I’m sure they could have just asked like the surveyors do but that requires manpower and a computer can do the same job.
Spyware places advertisements on your computer that pop up occasionally that are relevant to the things that you are interested in because it knows what your interests are now due to the information it has gathered about you through your internet browsing habits, the type of sites you visit, and the words you type in your searches.
So how do we remove spyware nuisances, It becomes a war between software programs since spyware is very hard to find for most people the only real way to get rid of it once it is on your computer is to get another software program that knows how to recognize spyware and remove it, fortunately this software is easily found and some of them will allow a free scan of your computer before you purchase.
http://www.advantage-power.com/computing/how-to-remove-spyware.html