As a society, we expect advertising. We are used to the idea that advertising provides a source of revenue for businesses that would otherwise find it difficult to charge for their service or content, keeping television, radio and the Internet available and mostly affordable for the average citizen.
Ads have become an essential part of the Internet economy, and will likely stay that way for the foreseeable future. As such, it is important, at least for the health of some sections of the software industry, to make the distinction between spyware and ad-supported software.
Again, as stated in the section above, there are no official or legal definitions of these types of software, but as a generally accepted guideline, ad-supported software can be defined as a freely available product that is funded by advertising.
Of course, this means the entire Internet is essentially ad-supported software, but I digress… ad-supported software products will inform you prior to installation that advertising is part of the provided package, and that information may be transmitted from your computer to aid in targeting these adverts, allowing you to make an informed choice.
Ad-supported software is a major source of revenue for many smaller software companies, and can provide consumers with economical alternatives to costly software. A good example of ad-supported software is the 'sponsored mode' of the popular Eudora mail client. Note the presence of advertising is clearly stated.
Ad-supported software can be an excellent way for small companies to market their products provided they are upfront with their methods. The point at which spyware branches off from ad-supported software is when the software does not clearly state its intended purpose.
Credit : http://www.pcstats.com/articleview.cfm?articleid=1458&page=3
