Corroborating PageFair's numbers is difficult. A May 2012 analysis ( download PDF) by ClarityRay, which like PageFair works with companies to counter ad blocking, pegged the percentage of browsers running blockers at 9.3%. But the two companies agreed on many points, including Firefox users' greater interest in ad blockers and technical sites' increased likelihood of being blocked.
Ad blocking is becoming more popular, O'Connor contended. Of the 38 sites for which PageFair has the most data, the annual growth rate was 43%, meaning a site that saw 10% of its visitors using blocking tools one year could expect that number to climb to 14.3% the next.
And appealing to users to not block a site they patronize has proved futile. PageFair offers site owners tools that make such appeals, reminding customers that the site depends on advertising to survive. The efforts have been disappointing.
"It's as if people don't care," said O'Connor. "Even for those who visited a site every day, only 3% to 4% would turn off ad blocking for that site. And those were smaller sites. For bigger publishers, it's even more difficult."
So what's the answer for sites struggling to deal with ad blocking?
"They have to rethink how they advertise," O'Connor said. "Rather than just chasing the click, they need to really engage customers in the advertising."
One way to prevent even more users from adopting ad blockers, said O'Connor, is to ditch the most intrusive and annoying ads — especially ones that use distracting animations and sounds — and rely on more discrete text-based ads.
The fact is, however, that display ads, which do not restrict themselves to text, are most sites' most effective advertising.
Some companies have taken to working with ad blocker makers — AdBlock Plus in particular — rather than fight the tide. Earlier this year, reports claimed Google had paid AdBlock Plus to get on the latter's "white list" as an acceptable advertiser. AdBlock Plus kicked off an acceptable ads program late in 2011, and does require large advertisers to pay to be on the list.
AdBlock Plus dismissed the claims, saying in a blog-based response that "you cannot 'buy' your way into the stack."
O'Connor said in lieu of a Google-like effort to get on AdBlock Plus' whitelist, he recommended that sites "put in place much more acceptable forms of advertising," those that won't prompt users to turn to ad blockers in the first place.
PageFair is working on a platform that will help site publishers do just that, perhaps with a two-tier system of ads, one acceptable to ad blockers like AdBlock Plus, another more aggressive, then ask users to opt in to one or the other.
"But short term, for some sites, it's already too big a problem," said O'Connor, again citing gaming sites as an example. "For them, they don't have time to wait for online advertising to adapt."
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