Washington: It has been reported on social media that Yahoo seems to be blocking access to its Mail service to some of its subscribers who use ad-blocking software in their browser.
In order to access their emails, and the accompanying ads, they have to turn off the ad-blocking extension, at least for Yahoo Mail.
It would seem that for the moment only some American subscribers have received this warning message: "We are unable to display Yahoo Mail.
Please disable Ad Blocker to continue using Yahoo Mail." It is the first time that a webmail service has acted in this way, but all the internet giants are facing a shortfall caused by the spread of Adblock Plus and other similar products.
Google is also attempting to respond to this type of software.
Many Google Chrome users have to watch an ad before viewing videos on YouTube, even if they've installed an ad-blocking extension. The same goes for Spotify.
And the SVOD service Hulu prevents some of its videos from being viewed when an ad blocker is detected.
In terms of the news websites, one of the fiercest responses has come from Germany, where access to the very popular Bild daily newspaper website is quite simply blocked when Adblock is activated.
The site also highlights its paid version, which is guaranteed ad-free. In a more unusual approach, the Dutch broadcaster RTL switches its videos to black and white for those who have activated their ad blocker.
Ad blocking, which is very common on computers, is now moving into mobile phones, resulting in a loss of revenue for publishers.
With Android, ad blocking via dedicated browsers has been possible for a long time. Now iOS is taking similar steps, as since the launch of iOS 9 in September it has authorized the use of ad-blocking software.
The Adblock Plus browser extension alone claims to have over 300 million downloads, all platforms included.