Hmm... I do like the idea of being able to donate to website owners to help make up for lost ad revenues, but it doesn't sound to me like the money will actually end up going to the site the user is donating to. If I donate to example.com, that money shouldn't end up in the hands of ABP heaven-knows-who.
PS: I've seen websites owners who have added already-existing payment services, such as Patreon, to make up for lost revenues. GHacks, for example, replaces empty ad holders (which of course are only empty if the user employs ad blockers) with buttons asking users to donate. That said, ABP is not doing anything new here: they're just trying to look like they're helping website owners for the sake of public appearances. They don't want to be called out for giving users the control they deserve hurting the web.