Mm, I see a small note on the second half of a bullet ( https://about.fb.com/news/2026/09/introducing-muse-personal-... ) that you can opt out of training. I know I’m a privacy weirdo since this didn’t make the FAQ in the OP:
“— People can change access or disconnect a service whenever they want. People can also opt out of their interactions being used to train Meta’s AI models.”
Guess you can opt out on the free tier? (I’m not much [read: at all] trusting of the company but I know many are fine either way.) Not saying I’m happy about having my emails on Google’s servers btw or would be comfortable connecting email to Anthropic/OpenAI.Wonder if opting out of training means they’d avoid using information gleaned from our emails to better serve their advertisers. Without knowing I guess I’d be concerned about even correspondents of mine using the service.
As for training, I'd be highly surprised if they use the data they get from APIs for training. But the conversation itself & thinking trajectories probably will, unless you opt out, like you pointed out.