I'm not concerned about my friends reading it and thinking less of me, I am concerned about my friends posting made up stuff about me. What if a potential employer read it. Totally plausible, totally harmful.
Imagine if it happened and I had no idea about dirtyphonebook.com, I wouldn't know to protest anything. Then I am out of luck with the employer. There are many avenues of abuse.
I don't want to search by terms, I want to search by my area and scan for people I may know based on the comments. It is like 3 word changes in an SQL query to add the ability to search by area code.