I imagine this may irk some googlers on here, but after Hangout's effect on xmpp / Reader's on RSS, I find it hard to discount the impact a built-in Chrome ad blocker would have on other generally available blockers. A lot of major sites still allow their content to be read by adblock users today because of the volume of traffic they'd have to shut out; but I don't believe that'd be the case once they start becoming a minority.