Facebook has figured out a way to display ads even when someone is running an ad blocker, and it intends to start using it. In a blog post today, Facebook essentially says that its ads aren't that annoying and are critical to its existence, so it's going to begin forcing ads on people who are currently trying to avoid them.

It is not an unreasonable position — Facebook is free to use, completely optional, and funded by advertisements — but the change is likely to tick off those who find ads frustrating enough to block. To remedy that, Facebook is giving users the ability to block ads from certain businesses, as well as ads that pertain to various interests, "like travel or cats." Its hope is that by letting users remove unwanted ads and only receive more personalized ones, the ads it does show will be far less annoying.

So how is Facebook doing it? Ad blockers are usually able to pick out ads because they're clearly identified as ads within a website's code. Most sites can't change that because advertisers want to wrap their ads in various data trackers, so that they can find out exactly how well they're performing. But Facebook seems to be at such a large scale that advertisers can't balk at changes; and so within the site's code, Facebook ads will now look just like any other Facebook content. (They'll still be displayed as "sponsored" to users, of course). It's possible that ad blockers will find a way around this in the future, but it'll be a lot more work for them.