I'm not sure I understand why Adblock still works? I mean, how can it be so reliable in detecting ads?
If I had a site with ads I'd try to make them as unobtrusive as possible and indistinguishable from my own content. A sidebar of images with urls only from my own domain. If an ad network is used to serve those images it can be proxies through my servers. There has to be some technical reason why this isn't the standard way of doing it (for example that it breaks advanced tracking, or that Adblock detects the actual contents).
I think it's because, so far, the reach of ad-blocking is quite small so there hasn't been a significant need to invest in anti-blocking measures.
An arms race in blocking ads designed not to be blocked would be interesting to watch. While it would be very easy to introduce text/images/video in such a way that hides the fact it's an advert (there will be heuristics, of course); I suspect it'll be more difficult to measure the viewership/click-through-rate of such ads, as that's what will give the game away and make signal the presence of an ad.
Ultimately it might come down to old-fashioned offline measures, similar to how billboards/magazines use third-parties to measure the reach of an advert without any tracking on the advert itself.
This would make small content producers suffer the most. While everyone knows and trusts the reach of a newspaper site, a blog that suddenly gets 20,000 HN visitors in one afternoon, what's that worth?
What hopefully happens is that either that advertising online becomes what it is offline: dumb and expensive ads displayed to people on billboards and in newspapers. This will effectcively kill the small operations that pay for servers and bandwidth through ads.
or
Ad networks will become content networks: a content provider (such as a blogger) publishes their content to the network who bakes it together with ads and displays it on the site in question. That is, you either get nothing or you get content plus ads.
