While surfing the web of Youtube content creators I ended up on a website that prompts the user for their date of birth in order to continue. No reason, no information about what it will be used for - just preventing the user from continuing without typing in this personal information.
"What year were you born?"
[Blank area to type in year]
"Enter"
Privacy Policy
It seems super spammy but is it legal? It's a little scary that people can be preyed on in this way.
Source: https://www.j-14.com/