How does one get started on creating a social community web application?

[eluser]BorisK[/eluser]
Shibuya,

like xwero said, you need to start with users, permissions, ACL and build on top of that. We are doing exactly that in our project. Actually, we've outlined the first two steps in our job posting at http://ellislab.com/forums/viewthread/75571/

Good luck with your project