There's around 100k posts and 1 million comments as of now, so it's pretty easy division to find out how much of the site is your own posts and comments (check your user page, it keeps track). Personally, I've made around 0.35% of the site's posts and 0.17% of the site's comments, how do all of you stack up?
Good post about how the community creates the space (so the social interactions) - not the Vanguard of posters and mods.