Starting with Adblock Plus 2.0 you can allow some of the advertising that is considered not annoying. By doing this you support websites that rely on advertising but choose to do it in a non-intrusive way. And you give these websites an advantage over their competition which encourages other websites to use non-intrusive advertising as well. In the long term the web will become a better place for everybody, not only Adblock Plus users. Without this feature we run the danger that increasing Adblock Plus usage will make small websites unsustainable.
via Adblock Plus – Allowing acceptable ads in Adblock Plus. I’m all onboard with this, in fact I’ve even written my own Adblock Plus filters to enable ads that are both interesting and un-intrusive.