It seems like there are quite a few products that cater for writing this year, each of these products have something similar like simple writing interface, make it habit enforce you to write daily, a chart or graphical display that motivate you to keep writing etc.
Some people might ask why we need this? I think this comment on producthunt is the best explanation - Getting creative still need discipline and routine, lots of best creative idea/inspiration happen after tons of discipline and routine practices. For example, I don't really write very well or interesting topic, but doing daily writing like this keep my brain work, when I see some news or topic nowadays, the first thing that pops in my mind will be is this worth it to write down today?
Starting of 2019 there are already quite a few similar products launched. It will be interesting to see how many will survive through the end of the year, it's not really a technical product, it's a more a community product, whoever builds the best community win.
It's hard and still early to tell who will be the winner, but one thing that really needs to ensure is, the platform should provide an exit way, this is why I asking for API for 200wordsaday, at least I can sync out my content.