Worse yet, measures against people running ad-blockers are sure to annoy some of them into retaliatory responses. For example, there are already plugins which attempt to click on all the ads on a page, so advertisers become concerned about click-fraud and offer less return to the site operator.
It would be very interesting to know the rates at which users disable their ad-blocker for Yahoo Mail, versus the ultimate account-abandonment rate from this "small" A/B test.
I keep hearing people say that, but I really don't think that's how it will turn out. Adblockers rely heavily on pattern-matching to work: scripts loaded from certain third-party domains, resources in particular subdirectories, markup structured with predictable element IDs/CSS classes, and the like. There are ways to break all of these: first-party ads, either by directly hosting them or by proxying your ad network; media served via embedded data: URIs or hash-based URIs; CSS which is minified, and randomized every few weeks; etc. These techniques may not be widespread yet, but I'm sure they will grow in popularity as the adblocking war rages on.
But hey, maybe ads will get a bit less egregious in the process.
First-party ads won't be trusted by the advertising industry, since it's "easier" to commit click-fraud. First-party ads for the originating site itself were never really the target of ad-blockers in the first place. (I mean, if you're surfing Amazon, you probably want to hear what Amazon has to say about Amazon.)
Third-party ads will always be easier to spot.
Finally, at least until advertising becomes thoroughly intertwined with content, it should be possible to block ads based upon their position relative to main content blocks. I.e., switch to blocking ads based upon behavior, and not URI/DOM regex.
Edit: I should clarify that, unless you're a major publisher, you won't have the skills necessary to participate in the ad-blocking war. There will be more developer mindshare given to the ad-blockers than your minor site can afford. Sure, there will be public or private anti-ad-blocking libraries--but which do you think is more likely to be up-to-date?
As a staunch advocate of adblockers: as is Yahoo!'s right and adblocker makers should not attempt to circumvent it.
Yahoo! doesn't have an implicit right to their code running fully on my machine but by the same token I don't have an implicit right to their services. If they've made it clear they think I am not making a bargain with them that they like then I respect that.
What I can't respect is whinging about adblockers in editorials but still serving me the content (cough, The Verge).
