The amount is probably very small - 1-2%.
At this point, there are 400 people viewing a subforum of the premedical forums. That is about 400 out of 1700 people on the entire site right now. The others are spread out among pharmacy, dental, etc. Of those 400, a lot will not be premed students; they will be med students, residents, etc.
So of the 1700 on the site right now, only (a guess) 300 or so are really premed students. The next question is whether or not they are applying this cycle or not. I would say half are and half may not be (maybe next year, like myself).
So when you really break it down, the number of applicants who are active on SDN is very small. This works out well for those of us on here since we get the advice of everyone who has already gone through the process, Lizzy, etc.... a sort of artificial selection, if you will. We get to sway the chances of getting the dominant gene (acceptance) by purposely adding knowledge.
The much more interesting question is how being a part of SDN (being informed) increases our chances of getting into med school. If half of all applicants get in with all things being equal, how does our knowledge fit in amount MCAT, GPA, ECs, etc. The reason I have taken ECs more seriously over the past year has had a lot to do with SDN (I realized it was imporant). That knowledge as well as the advice of applying early, knowing what to expect at interview, MCAT help, etc. is invaluable information. I would hypothesize that actively being a part of SDN (and actively taking heed to information and acting on it) greatly increases one's chance to get into med school.
Before I had SDN, I didn't know anything about rolling admissions, the "why medicine" interview type questions, and the importance of different ECs. This has a big effect on admissions, thus SDN has a big effect on admissions. In my opinion, of course.
