Last week, Facebook said it would circumvent ad-blockers on desktop to protect its ad business. The company tweaked the way it served ads to avoid being blacklisted by ad-blockers.
It didn't take long for the ad-blocking community to hit back, however, with Adblock Plus crowing about a workaround two days after Facebook's announcement.
In an update, Adblock Plus now says it's locked in a game of ping pong with Facebook, with the social network again updating its code to circumvent the getaround.
"The short update to all this is that Facebook’s sponsored posts, which show up in your feed, are not being blocked right now. Boo," said Ben Williams, spokesman for Adblock Plus.
The back-and-forth has come about due to Facebook changing the code that differentiates its ads from normal posts. In respose, the ad-blocking community adjusted its filters to detect that code. But then Facebook changed its code again in response.
According to Williams, Facebook's changes could mean that ads are no longer obviously differentiated as ads, meaning the US Federal Trade Commission might take an interest.
He said: "Clearly differentiating between paid-for and organic content is hugely important, because journalism is supposed to be that "fourth estate" which informs us about what politicians and businesspeople are doing.
"An ad is something different, because its intention is not to inform, but to market."
While Facebook is winning for now, there's an "unstoppable" community of developers working on counter-measures, Williams added.