For the given case, look for large amounts of added content that just happen to match up with a competitor's. Very few legit sites will add 1000+ articles/pages

For the given case, look for large amounts of added content that just happen to match up with a competitor's. Very few legit sites will add 1000+ articles/pages in a short amount of time, especially not ones that don't relate to say, product pages, category pages or other normally automated setups. And honestly, looking for ridiculous amounts of pages being added in short periods of time should be one of the first things Google flags for a website. Ignoring a few very unlikely exceptions (site is bought out and merged into another one, site goes viral to the same degree as TikTok, Amazon sets up another store), adding thousands or tens of thousands of pages in weeks, days or hours should at least get a site flagged for manual review. Similarly, sites with a large percentage of content copied from elsewhere (like those Stackoverflow ripoffs) should be easily downranked into oblivion. Forget AI, one of the biggest problems Google has right now is that obvious copycats are ranking as high as (or even higher than) the originals, despite the company clearly having numerous ways of knowing who the original is and who the ripoff is. Also perhaps treat different types of sites differently too. For example, often when a wiki is forked, you'll have two sites with similar content; the original and fork. Prioritise the one with more edits and activity, and you'll see things like Wikia/Fandom get rightly wiped out SEO wise. And yeah, definitely use social media as more of a benchmark for legitimacy, since virtually everyone uses it in some way to communicate online. If a site isn't mentioned by anyone who's been around for a few years or with a decent reputation, then don't rank it as high as one that said people are mentioning. Stuff like Hacker News and Reddit karma, likes/retweets/their equivalents, mentions on blogs and personal sites, links from wikis, etc should be seen as authenticity factors in a much more strict way than they are at the moment.