User Generated Content - controlling Comment Spam on your website
In March 2020 Google started to look for hyperlinks that had been designated rel="ugc"
What Google say:
" Comments are a great way for website owners to build community and readership. Unfortunately, they're often abused by spammers and nogoodniks, many of whom use scripts or other software to generate and post spam. If you've ever received a comment that looked like an advertisement or a random link to an unrelated site, then you've encountered comment spam. "