"You can't annoy someone into liking you"

Though global online-advertising revenues rose by 22% in 2011, websites that depend on selling their viewers’ eyeballs are worried. Around 9% of all online page views come from browsers armed with ad-blocking software, such as Adblock Plus, downloaded nearly 180m times since 2007, and 3.5m times in October alone...

Few sites have tried to fight back. In 2010 Ars Technica, a technology-news outlet, found that 40% of its users were blocking its ads. So it blocked their access for a day, but signed up only 200 users (out of 5m a month) for its ad-free version. Media firms are now opting for paywalls. Press+, a paywall provider set up in 2010, now has over 300 clients.

“You cannot annoy someone into liking you,” says Norm Johnston of Mindshare, a media-buying agency. But for many users the only good ad is an invisible one.