The problem is somewhat similar to twitter/facebook's:
- followers and following
- users add items
Subsequently you see the items added by all the people you are following.
Problem A: how to keep the query for items added by people you are following working well with growing datasets?
Problem B: we are seeing geographically disperse traffic. large userbase in the netherlands and brazil. any solution would probably need to allow for databases across multiple data centers.
We are running on a django/python stack. Already running edge server caching. (Anonymous users get the cached version, logged in user's version is run through a second level template parsing service first)