It's fine in tweets and even HN/Reddit comments, but it becomes a tacky affectation when used in longer form, deliberate content.

I wonder if unconventional writing styles are becoming the signal for deliberate content. If text is too polished– or even using certain punctuation– can lead to readers questioning whether AI assisted in the creation of the text.

A quick search shows that others have made this connection between Altman and lowercase and non-AI authenticity: https://ted-merz.com/2023/12/18/writing-in-lowercase/

It looks like this particular blog previously used conventional capitalization from 2017 to late 2023. The first post in this style appears to hint at a kind of shift in identity of the author, so perhaps, in this instance it is more a signal of personal expression or tribalism than non-AI-ness. Then again, we may see the line between the two continue to blur.