Or scrape the HTML directly instead of using an API. I'm pretty sure the clients I mentioned in the post scraped the old forum. APIs and SaaS wasnt a big thing a decade ago.

And I recall in my case there is not a big exodus but people slowly moved over with die-hard fans on both sides.

As a comparison, with 20MM the devs can probably build the new thing, serve media over CDNs and out-SEO reddit with some to spare.

I think moot and hiroyuki did try to monetize 4chan but with mixed success. See the 4chan pass and splitting of the SFW boards into a separate domain.