Lots of folks want to know how much it really and truly matters how much they are involved outside of work or in their undergrad programs. I simply put it this way: volunteering won't help you stand out, but not doing so may help you stand out in a negative way. That's a clever way of saying that most applicants have volunteer or community involvement activities that they participate in, so not having any may throw up a flag. B-schools are looking for driven, passionate and engaged leaders--not just professionally, but personally as well. The theory is that if you are passionate, this will spill over from your vocation and into your life in general. It's more about communicating the kind of person you are rather than what you are doing. Better to drill down deep into one extracurricular activity than to run out and volunteer at a soup kitchen a couple of times, or clean up the park, etc. Those things are important, and if homelessness or dirty parks are your passion, by all means participate in those activities, but the point is, pick something that is important to you and get invovled--really involved. From this perspective, I can make the original comment a bit differently: no, volunteering is not important if it communicates it was done as simple fodder for an application.