Ask YC: What Social network questions would you like to see answered?

Imagine you have complete information about the evolution of a relatively large (10^5-10^6 users) social network. Who connects to whom, when, and some basic information about each user.

What questions would like to see answered?

Which quantities do you think will be of most practical interest for the next few years?

Can you direct me to some standard (and not so standard) literature in this field?