Well, that was fast. Digg only just relaunched but now will be shutting down because they couldn't fend off the SEO bots:

When the Digg beta launched, we immediately noticed posts from SEO spammers noting that Digg still carried meaningful Google link authority. Within hours, we got a taste of what we'd only heard rumors about. The internet is now populated, in meaningful part, by sophisticated AI agents and automated accounts. We knew bots were part of the landscape, but we didn't appreciate the scale, sophistication, or speed at which they'd find us. We banned tens of thousands of accounts. We deployed internal tooling and industry-standard external vendors. None of it was enough. When you can't trust that the votes, the comments, and the engagement you're seeing are real, you've lost the foundation a community platform is built on.
This isn't just a Digg problem. It's an internet problem. But it hit us harder because trust is the product.

This is a problem we're of course familiar with on Product Hunt, and is something the team is working on every day.