If an entire UI (content plus ads) is drawn with wasm onto a canvas (the way Qt WebAssembly does it), it will be impossible to use CSS to hide ads, and possibly more difficult to modify the script to disable the ad-loading functions.
Doesn't sound very feasible, as this would make user experience probably much worse. No native elements, no browser integration or extensions, interaction with the page, and accessibility. They all would suffer.
Right but my point is you can _already_ do this in javascript, but people largely don't. The playing field doesn't change with WASM. If some WASM code creates a canvas-based ad, we can use the usual tactics to block it (delete the element by ID/selector/etc or block that particular WASM payload)
Google is an advertising company. It would make sure there is a way to get your site indexed, perhaps by providing an alternate machine-readable version just to them. As a bonus, that version would not be available to potential competitors.
This technique is essentially the same as websites made entirely in Flash back in the day. And back then, the only way to have Google index your site was to provide a separate (hidden) version that used normal, semantic HTML.
Googlebot runs a full web browser these days and executes javascript to a certain extent. WASM will have the same treatment if/when it becomes widespread if it doesn't already.
