I'm sure Quora views took a hit after ChatGPT. Not like Quora was any good before ChatGPT, they just managed to get to the top of Google results for a lot of common questions.
Now, Poe by Quora was trying to go big on custom agents. The GPT Agents announcement on DevDay was a fundamental threat to Poe in many ways.
I'm convinced that Adam D'Angelo probably had some influence on the other two board members too. He should've left the board of OpenAI the moment OpenAI and his own company were competing in the same space.
Also keep in mind that a year earlier in Spring 2017 Sam Altman led Quora's Series D, after YC previously joined in on Quora's Series C in 2014. So the two of them clearly had some pre-existing relationship.
I don't think OpenAI and Quora (the product) are a serious conflict of interest. You claim "I'm sure Quora views took a hit after ChatGPT" but I really doubt that's true in any meaningful way. Quora's struggles are a separate issue and predate the GPT craze of the last year.
Nor were Poe and OpenAI competitors until recently; Poe was simply building on top of OpenAI models, the same as hundreds of other ventures in the space right now.
However...I do agree that the GPTs announcement two weeks ago now creates a very clear conflict of interest--OpenAI is now competing directly against Poe. And because of that, I agree that Adam probably should leave the board.
The timing also raises the question of whether booting Sam is in any way related to the GPTs launch and to Poe. Perhaps Sam wasn't candid about the fact that they were about to be competing with Adam's company. The whole thing is messy and not a good look and exactly why you try to avoid these conflicts of interest to begin with.