In life, I believe, the only way to live is to do. So if one has a dream and it involves you achieving some sort of action, then you must go where it is your dream plays out and get into the action. If your dream is to build the world's fastest car, go to the Grand Prix, quite literally.
There is no hope of achieving your vision if you don't act on it, and the best place to find inspiration for your next action is to be in the environment where the action takes place. So if you want to grow a tree, you better go to the garden.
In reference to social innovation, when one spots a social problem that one would like to solve, you would have to start by going to the problem and having direct experience and knowledge of it. There is no way of dealing with social issues without being socially involved in it.
However, this is becoming an interesting debate with the advent of the internet. The internet allows us to go places and connect socially with people we have never met so this means that we may be able to go to where the action is without physically going there nowadays.
In spite of this, I am still a strong believer in enthnographic research methodologies and therefore I would argue that physical presence and real world interaction is vital for any social innovator to be successful in their endeavour. Without the richness of personal experience, ideas and solutions are lifeless and irrelevant.
A social innovation cannot take place from the ivory towers, it can only happen from the ground.