Use NoScript (firefox), ScriptNo (chrome), etc.
None of the "bad" ads work, including all that jump-in-your-face noisy pop-over bollocks, and the insidious mouse-pointer-tracking shite. Most of the "normal" ones are gone too, but they were all surreptitiously tracking your activity.
The only ads that remain, are plain HTML images with HREFs.
I call this kind of ad-blocking "ethical" because if a website owner honestly wants to promote someone else's product, without using some parasitic ad-network with a shedload of ulterior data-mining motives, then he still can. He or the ad-network just has to take all the crap out and it'll work fine.
The problem is that the ad-networks pay websites more because they are making money out of slurping and mining user's data (perhaps more than they are paid by advertisers for marketing their products). THAT's what's unethical if you ask me.
The downside is that