There are many facets to this question. I'm guessing you're referring to the recent explosion of activity regarding Kony 2012. The quick and dirty answer is yes, any type of awareness of something by people with the means to act, can lead to the eradication of something. The reason the answer is yes is that eventually with millions of people being aware of an issue, it may reach person(s) who have influence or the means to address the problem directly. Social media/online communities are just that - communities. The fact that many people on them may do nothing is irrelevant. We don't need everyone to do something. We need messages to reach the right parties, so we don't sit in blind ignorance to the worst parts of human nature and not act because we don't know. Knowledge is power.
So the more specific answer to your direct question is no, me writing an answer to your question, for example, doesn't directly result in the stopping of this practice, and I'm only responsible for the actions that I can either control or effectuate. But I AM responsible for that. What is more repressive to me are the blowhards who try to tell people like me that I should stop spreading messages of hope or of actions they could consider taking, because it makes them uncomfortable. It feels as though those people are merely trying to justify their behavior.
That said, it's vitally important, once a message like Kony 2012 is unveiled, that there is an abundance of transparency to demonstrate exactly who they are, what is their intent, what my interest or funds go toward, etc., because, unfortunately, everyone has to compete for the mental air space of all of us, and there comes a certain responsibility inherent with that. I understand that the group has chosen to focus on awareness as the "action" that people can take - that's good, because it's tangible and doable. I am also interested in the answer to the next question, which would be, "Okay, you have my attention. Now what?" I may or may not be able to do something about it, but it would be good to know.