Yellow pages were business listings. They were also sorted by category, then alphabetically within a category, which is why so many businesses names started with "AAA."
Some of us who lived in that era and who are tech savvy think the privacy paranoia is little more than the equivalent of TSA's security theater at airports.
There is nothing stopping anyone from finding out exactly who you are, where you are, and what you're doing. We all carry locator devices today that never existed in the era of the phone book.
Our social security numbers weren't in databases with internet exposure where financial companies with information "security" could have them leak. Everyone's has leaked now.
A lot more people than you'd think are easily googled right down to address, family names, current phone number, past addresses... you name it. Leaks happen every single day and big data is everywhere monitoring your everything.
Having your name, address and home phone number in a book that only has regional numbers and isn't widely distributed beyond the local scope is the the smallest privacy concern.
Seems like the average young person is fine posting photos and videos on all the social media platforms journaling their whereabouts and habits too.
I was in 9th grade, went to school with the girl I liked. She was shy, but cute and fun. I asked her out, and was flatly refused.
Starting the next year, I changed districts. Thought about her a lot for a couple years. Broke out the phone book and searched her last name. Went through about 6 before I found her and asked her out again. We dated for about 3 more years until things started getting pretty serious and I decided I wasn't ready to get married in my teens.
I remember for a brief time Google offered up names, addresses, and phone numbers in their search results. Then after like a year (maybe less?) people decided to get freaked out over it. They offered a way to opt out, then just removed it entirely.
I also remember back in the 90s, my mom and stepdad buying a 7 disc set of phone numbers and addresses. No idea why they did it... But it was a thing.