Yahoo! says it is testing a feature that prevents some users of the Adblock extension from accessing their webmail accounts.

Netizens have reported on the Adblock Pro support forum being unable to use the Yahoo! Mail service with the ad-blocking extensions turned on.

When trying to log into the Yahoo! webmail, they are met with a blank screen and a dialogue reading "Uh oh. We are unable to display Yahoo Mail. Please disable Ad Blocker to continue using Yahoo Mail."

This affects folks using Google Chrome and Mozilla Firefox web browsers.

Yahoo! confirmed it is indeed blocking the use of Adblock on its webmail service, but said that it was only doing so for select users as part of an A/B test.

The message that greets some Adblock users

"At Yahoo!, we are continually developing and testing new product experiences," the Purple Palace told El Reg. "This is a test we're running for a small number of Yahoo! Mail users in the US."

Yahoo! did not provide details on precisely what was being tested or how long the test would last. In the meantime, the affected Adblock users will still be asked to disable their blocker in order to view the webmail service. ®

Hat tip to @Pinboard for the sub-headline gag.