Three have been so valuable for my DD’s college search: The first was Admissions->Specialty Topics->Athletic Recruits. My DD plays in a niche sport with a young coach and will be the first to go to the NCAA at her club, so the information I gathered about college sports recruiting was invaluable.
Secondly, the “Colleges and Universities” forums devoted to each college she was interested in were very helpful narrowing down her college list. It was invaluable reading posts from kids and parents who had the same questions we did about each college/university, from the schools’ social scenes, to merit aid, to what to wear to the interview. This forum saved us money - based on our visits and what we read on CC, she was able to cross schools off the list and not have to spend the time and money applying. Now that she’s been accepted ED1, both of us are enjoying corresponding with the other ED1 students.
As others mentioned, the NM threads helped us understand the PSAT/National Merit process. Because of it, my DD was able to set her sites on a score knowing what the historical NM cutoff was for our state.