Inbox Zero is a system for managing email that aims to keep an inbox empty by deleting unnecessary emails, acting on important ones, and delegating tasks whenever possible. However, some argue that it's impractical to spend too much time managing email and propose alternative systems like Inbox Infinity, which involves setting up autoresponders and not responding to non-essential emails. The effectiveness of Inbox Zero depends on individual circumstances, with some people finding it works for them while others may not have the luxury of being unresponsive due to their job requirements. Ultimately, the key is to find a system that works for each person and stick to it, rather than focusing on a specific approach like Inbox Zero or Inbox Infinity.