Blogging: the search for knowledge synthesis

I was asked why I blog ( or more specifically why I enjoy it) recently. At first I had a fairly lame answer. After more consideration I realize I am searching for knowledge/information - a part of that search is expressing ideas publically and getting feedback. My life is enriched by learning from others but that requires sharing of thoughts - is this the essence of blogging?

At one the recent Social Software meetings I asked what the end goal for social software for users would be. I am not sure I got a good answer, but then I do not believe there is one good answer. On reflection the question may be how does "Social Software" provide an environment (and the tools for Marc) where users can find their own reason to interact and grow in different ways.

Should the goal of Social Software to provide applications or infrastructure?