This document discusses the Firefox add-on Firesheep, which allows session hijacking on unsecured Wi-Fi networks to steal Facebook cookies and change others' statuses. It demonstrates how Firesheep works through man-in-the-middle attacks like ARP poisoning and describes some protections like using SSL, firewalls, and not sharing Wi-Fi networks. It also mentions the Blacksheep add-on that detects Firesheep to make people feel better about security.