Interactive Ads

Many websites  these days use interactive advertisements in order to better assess your interests and attempt to guess what you like in order to provide you with advertisements that you are more likely to respond to. But is this an effective way to boost profits from ads, or is this an invasion or privacy? Many people, including myself, don't like the fact that websites are tracking web traffic from my computer and selling it to advertising agencies in order to provide me with advertisements they think I might be interested in. Is it right for websites to use this information for profit? It isn't exactly private information, but personally I don't really think its any of their business what sites I'm visiting and what interests I have. Is it right for ISPs (Internet Service Providers) to allow this kind of snooping on peoples' web traffic? In fact, this opens up a few security risks as well, since someone could potentially pose as an advertising agency in order to acquire this information. Is this information dangerous, and could it be used to exploit peoples' security? Probably not, but that doesn't make me comfortable about it.