My next product will be Diary Email (diaryemail.com) it’s a private diary that you update using email. Send a note to email@example.com, and it will be added to your journal that you can access online. You can also invite your friends to receive entries you send to firstname.lastname@example.org. I call it anti-social network, but you can see it as a mailing groups.
It's mostly finished, I only need to optimize it for mobile and I integrate Paddle. I decided to have paid plans since day 0 and also provide polished experience.
During the development, I had to parse emails’ HTML and then nicely render it. I had a similar problem with Telepost except that input was in Telegram format. I came up with a universal solution that powers Diary Email and soon will be merged with Telepost renderer and be used in future projects. I call it XJSONML. Fancy, right?