NEW YORK: Facebook is blocking ad blockers on the desktop version of its service, saying well-made, relevant ads can be “useful”.

At the same time, the world's biggest social media company says it is giving users easier ways to decide what types of ads they want to see — unless, of course, the answer is “none”.

Ad blockers filter out ads by refusing to display page images and other elements that originated with a known ad server. But Facebook has found a way around this.

Beginning Tuesday, the desktop version of Facebook will show users ads even if they have ad blockers installed.

The changes don't affect the mobile Facebook app, which brings in the bulk of the company's advertising revenue. As with most new Facebook features, the changes are being rolled out to users over time, so some people might see it before others.

Facebook needs ads

While couching its move in the language of customer service — primarily by reiterating its premise that ads serve a purpose if they're relevant and well-targeted — Facebook is also upfront about needing them to make money.

Andrew Bosworth, a Facebook vice president, pointed out in a blog post that Facebook is a free service that's only able to operate because it makes money from advertising.

In the most recent quarter, Facebook made $6.24 billion in advertising revenue, an increase of 63 percent from a year earlier.

Mobile advertising (which is not affected by the changes) accounted for 84 percent of this.

Cat-and-mouse blocking

Several publishers, such as The New York Times have tried to work around ad blockers by asking users with ad blockers installed to turn them off in order to be allowed on a website.

Other technology can “reinsert” ads that have been blocked. But there are ways to configure ad blockers to stymie these efforts as well.

Facebook's ad-blocker blocker works by making it difficult for software to distinguish advertisements from other material published on Facebook, such as photos or status updates.

But while users won't be able to stop ads from showing up, Facebook says it wants to make it easier for people to control the types of ads they want to see.

For example, if you don't want to see ads from a specific business, or ads that target a specific category like travel, cat owners or wine lovers, you can say so.

“We also heard that people want to be able to stop seeing ads from businesses or organizations who have added them to their customer lists, and so we are adding tools that allow people to do this,” Bosworth wrote.