Bluesky users, if you do not want to provide your birthdate to US VC funded #Bluesky PBC, simply join one of the other completely independent decentralized AT protocol instances listed below:
😉 [end of list] (/s)
Alternatively, you can just come on over to truly decentralized public social media where your personal data will not be exploited.
EDIT: 🤦♂️ It seems Mastodon also now asks birthdate during sign up, but with substantive differences. See clarification below.

Mastodon - Decentralized social media
Learn more about Mastodon, the radically different, free and open-source decentralized social media platform.
