At one time, my blog was about community, but my community was always rather small and uninsulated. I attracted few friends. That has always been true for me. I can watch people enter my social circles, merge in, and become part of that circle, while I can only make it into the periphery and stay there. I envy how those people can make friends. I envy how people want to make friends with them. In my life, that situation has never been true. Changing blogs won't change that dynamic. So the "community" thing that LJ or DW offers gets me nothing.
Changing blogs will also not solve the problem that I don't know who people are. Really, I can go to any friends list and have no idea who is on their friends list. I presume that I must know some of those people, but they remain a mystery. So, a find an pickle and egg problem. I still don't know my way into those social circles.