Advertisement. I hate you, so much. At its core, it isn't such a bad concept. Tell people who will probably want your product or service about it, so that they get what they want. But in implementation it has become something of a monster.
The first problem is the nature of advertisement, Trying to convince people to buy things that they don't need, whether they want it or not. This at it's core is mind-control and a severe form of manipulation. In my opinion its un-ethical when it is done without explicit permission.
A EULA does not count! If I order your magazine, that is explicit permission. If I /request/ your email notifications of hot deals, that is permission. If you find my email or address somewhere on the web, and sell it to another corporation, who then uses it to bombard me with trivial bullshit. THAT IS NOT PERMISSION.
The second problem with it, is brand recognition and propaganda. "Our brand is better, because its not their brand." Every few days I hear the "Coke vs Pepsi" debate, somewhere on the internet, or offline. This is a false ideology, this is tribal warfare for the sake of taking your money. Is one better than the other? No. (for which I will be harassed, I know it.) Are they significantly different? No. Are the corporation's particularly different in their behaviors? No.
Today I surf with adblock+ and noscript turned on, at all times. Internet explorer is a great browser to go download an alternative. I stayed on firefox for quite a while until it started becoming the target; I was waiting for adblock+ and noscript to emerge on chrome.
Now I'm on chrome, and I'm just waiting for the target to be fully acquired and require me switching to something else. In this game you cannot win against malice unless you keep changing, keep evolving. The moment you stop changing is the moment you have to -reinstall- nuke your operating system from orbit, because its the only way to be sure.
There are many people who try to say not to use adblock because the sites you visit need money. My counter to that is, the site needs money? it should find a way to pay for itself without harassing its customers and putting their lives at risk.
This is my way of voting with my wallet, if enough people block a site's ads, eventually the site will have to find a new source of income. It hasn't worked yet, but doesn't mean I wont stop trying. If one or two sites fall over due to being unable to keep up with the changing environment, well, that's just too bad.
And in summation; You wouldn't fuck a diseased crack whore without a condom, don't surf the web without proper precautions.