as a great example of a startup blog although it's gotten more corporate and self-centered lately. I think they might have also cleared out their early posts. They were early to the vector database trend and were working on it before the ChatGPT revolution and they used blogging to get visibility. They did all the obvious SMO things, turns out I am wearing a "LOVE THY NEAREST NEIGHBOR" T-shirt today which they sent me because I gave some kind words.
In your case you have some concern about whether this should be public as you might be under NDA or just think that some of your stakeholders might rather keep things under wrap. You've mentioned investors but I'd think that other people involved might have concerns too.
Many people would say you should be thinking about what goals you want to attain: keeping investors sweet is important, but perhaps you could build buzz about a movie before it is released, or get messages out to people who might work for or with you, etc. Left to my own devices I would be inclined to "write a blog because I want to have a blog" but the people who advise me would want me to have specific goals in mind.