I wonder if the real value isn't just being a support (except for snarky answers). Just a place for people to post and work out their anxieties about the process. Sort of like group therapy.
The danger, of course, is people getting 'bad' information about how to deal with certain issues. I also do not believe that anyone can post their stats and get any real answer on being admitted. I think that the admissions process is far more nuanced and complicated than people realize.
And each school has certain goals in terms of who and how many they want to admit. So blanket advice isn't that useful. I think that the most useful advice you can give someone is to
1) work on the written responses to questions on the application - essays,etc and make sure you're really saying something about yourself (besides demonstrating that you can write.)
2) Look around at a lot of schools - don't just stick to schools everyone knows about. There are some places off the beaten path that can be great. So keep an open mind - visit if at all possible. Don't get your heart set on one school and only one school. That's just misery waiting to happen.
3) Get your ducks in order and get things done on time - including giving teachers and other recommending time to do a nice job on a reference. Tell your reference about yourself and what you're hoping for. It will help them. It's one thing to have a student who is good academically - no problem saying that. But it helps to have a little more understanding of the student, other than the fact that they perform well in your class.