I couldn't find much about diff.blog with a cursory glance over the internet, so I went looking.
On diff.blog itself I discovered a post from Roman Martin's blog when diff.blog found him back in 2020 the same way they did me recently.
Here's a Hacker News subthread from 2020, where the creator of diff.blog, Vishnu KS, is promoting it. Here's a smaller subthread from 2022, and another subthread from 2021, and one more from 2020.
One of the HN threads was linked in a blog post from jerieljan.
There've been HN submissions of diff.blog, and a Reddit post, but none have taken any traction.
diff.blog is briefly mentioned in techweez article, a comment on a contentmarketinginstitute.com article, and a Medium post from Oleg Semerikov.
That's all I've found so far, seems a small project but I wanted to dig up as much discussion as I could!