They're meant to be pages for very easy combinations of text, mixed media, embeds, etc. — let more people create fun/interesting places on the internet. [2]
I started working on mmm.page in Feb 2021, and launched it that May on Hacker News [3], then it hit $2k/mo last year, and has been growing steadily since. There are roughly 30,000+ users at the moment. Revenue has been trickier for this project because it's a SaaS aimed at consumers, who are more price sensitive — but the flip-side is I love working with all the people who use the platforms. Just today, someone shared this moodboard that captured exactly how I've been thinking about it mmm.page [4]. Some other fun examples here [5]. I'm planning a second launch in May. Hopefully some good news to share there.
One note: it's a website, and most people edit it on desktop, but a surprising # of users convert /after/ trying it on mobile. I also found the conversion rate increased significantly after I made the homepage itself editable — thereby demo'ing the product without a login. Just a small note.
Anyway, feel free to reply or DM on Twitter if you have questions — especially re: solo bootstrapping "fun" consumer products that are trying to also become self-sustainable.
[1] https://mmm.page
[2] https://twitter.com/xhfloz/status/1631746024120221698
[3] https://news.ycombinator.com/item?id=27128424