No it's not: https://computermobilepanel.nielsen.com/cmp/landingeng.jsp
GP was specifically asking about "back in the day", the comparison should be about the volume of data between then and now
You're quoting a different person, and clearly not, or they wouldn't be speculating on Nielsen's abilities in the present tense.
No it's not: https://computermobilepanel.nielsen.com/cmp/landingeng.jsp