Patterns for building social network type applications?

Question

I need to design / architect / develop a web based social network type application.

Basic functionality:
- users create accounts on the system
- users agree to

Answer 1

The key to success for social networks is not the technology on which it is based but the problems they solve for the users. If the users like it, you're doomed for success even if your technology is crap.

[EDIT] How is it implemented? Check any SQL-based user role system. In this case, every user is also a role which can be added as "allowed to access" to any object. Depending on how many objects you have and how fine grained the control should be, that can mean that you have a table with three columns: OBJECT, USER, ACCESS_TYPE where ACCESS_TYPE can be one of OWNER, READ (friend), WRITE (close friend).

This table will become pretty large but a few 100 million rows is not uncommon for todays databases anymore.