Some sites won't allow you to access their articles if you have an ad-blocker enabled. Sometimes you can get around that by turning off Javascript for that site, but you lose some of the content — usually multi-media crap, so it's usually not a big deal. Most of the time, I just want to read the article.
I don't mind ads if they're non-intrusive, but all too often, they make reading the article pretty much impossible. Who can read with all these videos playing with audio and popups. If they're not intrusive, I'll pause my ad-blocker on that site and allow ads. Otherwise, I use a Javascript switcher (Quick Javascript Switcher) to turn it off.