https://www.wolfram.com/legal/privacy/wolfram/

> We may collect both Personal Information (PI) and non-Personal Information (non-PI) about you through your experience on our websites, from your use of our services and products and via other voluntary contact with you (collectively "Services").

> The PI we collect through our Services primarily consists of information you submit to us. Because participation in our Services is voluntary, you have a choice of whether or not to disclose such information. The following are categories of PI we have collected in the past 12 months:

> Identifiers

> Examples include: a real name, alias, postal address, unique personal identifier, online identifier, Internet Protocol address, email address, account name, Social Security number, driver's license number, passport number or other similar identifiers

Now add birth date to the list.

No, they're just storing pieces of pi.
There was somewhere a joke program that "compressed" data by saving its offset in the digits of pi.