P4Pirate is an Index Archive. we work similarly to Google. But with a bit of change, we mainly focus on special links to be added to our library and we keep track of the links.
As for what we store, we do not store any file on our server. When someone submits any link we don't store any IP or any data related to users. We do use analytics.google.com to keep track of daily users. if you are wondering why then this helps us to expand our staff to accommodate more users.
For now, the goal is to expand the library more and help others.