Are they effective?
Yes. Techworld tested six leading products (Chrome + Firefox versions) against a range of websites known for ad-heavy content and can report that all were extremely effective, so much so that it's not hard to see why publishers might be worried. Two were even able to bypass sites that asked users to turn off adblockers in order to read content, which must be even more of an anxiety.
The only small fly in this was that not all adblockers work equally well in all versions. Some seemed more developed on Chrome than on Firefox and in one case was more effective on the former than the latter. Adblockers are usually available on all major browsers, including in addition to the two mentioned, Safari, IE and Opera. Mobile adblockers are a different category of product that is earlier in its lifecycle but Android and, more recently, IOS apps are certainly in evidence on app stores.
The Acceptable Ads controversy
From the outside it's incredibly hard for the uninitiated to tell one adblocker from another. There are dozens to choose from and all claim to do the job well. The important thing to remember is that while none of the well-known adblocking brands charge for browser extensions, they are in still business. A growing number are involved with the controversial Acceptable Ads system, set up by market leader Adblock Plus in 2011, which charges some large advertisers to bypass adblocking. Others simply gather anonymous data to sell on while a third, smaller group uses browser tools as loss leaders to promote subscription products in other areas of security.
Acceptable Ads is not popular with websites, a growing number of which have described it as a conflict of interest. Adblockers are supposed to filter out ads but this program makes its money by taking money to turn that off for some ads. This aspect of blockers could eventually attract the interest of EU regulators. To the cynical, adblocking can look like a clever example of a middleman business that inserts itself between end users and advertisers in order to extract a toll.
It's a live enough issue that in March 2016 UK Culture Secretary John Whittingdale used a speech to describe the adblocking business as a "modern-day protection racket," a clear warning that governments are starting to take a concerned interest in the implications of adblocking on the publishing industry.
"Quite simply, if people don't pay in some way for content, then that content will eventually no longer exist. And that's as true for the latest piece of journalism as it is for the new album from Muse," The Guardian quoted him as saying.
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