Legitimate YouTube uses (the padlock icon in your address bar), which encrypts data between you and Google. Many free "Unblocked 77" proxies do not support HTTPS correctly. They often use HTTP , meaning everything you type—including your password if you try to log into Google—is sent in plain text. A network administrator (or a hacker on the same Wi-Fi) can read your login credentials instantly.
allow you to browse via their servers. While convenient, they often struggle with high-definition video streaming. Browser Extensions : Extensions like youtube unblocked 77