Why are there many Monero addresses starting with 4JUdGzv…QvVCjZb?

Question

So far I've found:

• 4JUdGzvrMFDWrUUwY3toJATSeNwjn54LkCnKBPRzDuhzi5vSepHfUckJNxRL2gjkNrSqtCoRUrEDAgRwsQvVCjZbRx8NCvspxJMRJcG69H
• 4JUdGzvrMFDWrUUwY3toJATSeNwjn54LkCnKBPRzDuhzi5vSepHfUckJNxRL2gjkNrSqtCoRUrEDAgRwsQvVCjZbRyrP3MvTGHZ5ASzpW8
• 4JUdGzvrMFDWrUUwY3toJATSeNwjn54LkCnKBPRzDuhzi5vSepHfUckJNxRL2gjkNrSqtCoRUrEDAgRwsQvVCjZbRydwE9i8Yg26PQWw8e
• 4JUdGzvrMFDWrUUwY3toJATSeNwjn54LkCnKBPRzDuhzi5vSepHfUckJNxRL2gjkNrSqtCoRUrEDAgRwsQvVCjZbS31oxhFoqyC1zg7KGP

These come from:

• my XMR deposit address at Poloniex
• the donation address at www.monero.how
• a random post at forum.bits.media
• a random post at YouTube

Answer 1

They're all Poloniex's deposit address. The bit at the end is the payment ID used to identify the depositor's Poloniex account. You can read more about integrated addresses here: What is an integrated address?