Here are the details, for anyone who hasn't read about it yet.
This sounds like the most promising new idea in digital advertising in a while, but I'm not optimistic about its chances to succeed if it's limited to the Brave browser. Brave has microscopic market share and is marketed to a privacy-focused nerd audience that hates online advertising.
I don't think BAT can possibly succeed unless it also gets adopted by at least one other browser, preferably Chrome (which has the most market share). Ideally you'd want to get every browser on board, but I think even if they wanted to do this, they'd have trouble getting Apple, and Apple's browser has massive mobile market share.
I also find sentences like this one a little hand-wavy:
Ads are then anonymously matched with customer interests using local machine learning algorithms.
That's an easy sentence to write, but achieving good relevance based on local machine learning while meaningfully preserving anonymity is a really hard problem. And I think advertisers aren't going to like not owning that data.
I'd like to see this succeed, but I think the odds are stacked pretty heavily against it at the moment. But we'll see!