Can posting information about extracurricular activities, statistics, and test scores put an applicants chance for admission at risk?
Are college admission officers reading and documenting data from posts pertaining to their schools?
Ah, the power of anonymity. Counselors have no idea who “h1c2p3” is. And what is posted here does not, and should not, matter to the college admissions officers. I’d bet that few of them know of this forum, and even fewer read it (and next to none will remember, or care, what is said come decisions time). You could claim many things about yourself here, but what matters is what is presented in your app.
thank you!
I agree that you needn’t worry about adcoms seeking out your individual application and rejecting it based on what you might post here about scores, ECs, etc. I disagree that few adcoms know about this forum. If you look at individual school forums, you’ll see that many include posts from adcoms, who are identified as school reps on their CC profile pages. Two that come to mind, because I read those forums frequently, are @“Dean J” on the UVA forum and @W&MAdmission on the W&M forum. There are several adcoms active in the Musical Theatre forum, as well.
CC is seen as a marketing tool by admissions offices, so yes, many are aware of it. (Notice all the ads for schools that pop up when you’re here.) Adcoms are too busy to try to pinpoint which poster corresponds with which of their thousands of applicants. BUT! You are never as anonymous online as you like to think you are. CC isn’t an obscure discussion board anymore. If you read here long enough, the odds are good that you’ll recognize someone who is talking about your high school. You’ll sometimes realize you know the poster in IRL.
I’ve seen posters over the years talk about getting away with cheating, ED violations, etc. Those folks have something to worry about. You never want to make someone on CC curious about who you are - it’s just too easy to find out.
You seem to think that admissions officers have too much time on their hands. 
I think @frazzled1 's reply nailed it.