Only if its annoying enough for someone to write adblock rule for that particular website and push it into popular lists (EasyList, Peter Lowe’s Ad and tracking server list, etc).

Personally I only do it when my Mum asks me ;-) and never block native (siglent banner on eevblog)/regional relevant (small town website with static ads for local businesses) ones.

How does an ad look like?

Ad blockers will block images that are standard banner ad size. Maybe a text ad has "ad" somewhere in it's in CSS. We do only internally hosted ads and non-JS text sidebar ads and they're happily blocked by all major ad blockers. Doing everything "right" is no defense.

I'm not saying you can't make ads completely indistinguishable from content but I also don't think that's the solution that we want either.

Some people just don't want ads. Paradoxically, the sites I care most about are the ones I want to periodically visit, and enjoy without the ads. So the ad blocker will have filters fine tuned for those.

Is that a sustainable business model? Well, no. There's a direct donation on sites nowadays luckily.

Thanks :-) I didn't know they also look for common banner sizes.

CSS classes and IDs match certain criteria, like being prefixed with "ad" or suffixed with "banner" and having a rendered size that matches an ad box (eg: 600px by 100px).

The ad blocklists are maintained by humans so they can block whatever elements that can be matched by the ad blocker's filter rules.