I wonder why it was surprising for some to read this tweet. Startups will change their priorities daily. Business plans are against the idea of running a startup.
I mean his article on "The Equity Equation"[1] seems to be written by someone who has read a balance sheet.
I don't think a "business plan" is literally just any words, written down, that are related to "business".
It is likely a specific and defined thing.
>What is your company going to make?
This question is asking what your business is planning on making.
Edit: This comment includes more relevant questions https://news.ycombinator.com/item?id=30319753
afaik there is no legislation defining a business plan. It might say business plan at the top, it might be a whitepaper, it might be a tweet.
Make money, lots of money
There we go, a business plan, its not a good business plan, nor a traditional one nor even a very comeplete one, but a plan nevertheless.