Contract hash is not unique for each deploy?

Question

I created a contract.

https://ropsten.etherscan.io/tx/0x74426948905cd6e70e8b9d64a660b3c179b7c8a224ca5cd0234842768eb501db

The contract hash is 0x692a70d2e424a56d2c6c27aa97d1a86395877b3a

etherscan shows the contract has many transactions. The latest three transactions are mine. But the other txes are sent by someone.

https://ropsten.etherscan.io/address/0x692a70d2e424a56d2c6c27aa97d1a86395877b3a

My contract was copied and pasted from tutorial page. I think this is the cause since data is same. Is this my understanding correct?

pragma solidity ^0.4.0;
contract Addition {
  int num = 0;
  function add(int a){
    num += a;
  }
  function get() returns(int){
    return num;
  }
}

Answer 1

The contract address is unique for each deployment. You (or anyone else) can't create a different or same contract with the same address.

That people have transacted with your contract doesn't mean anything in this instance.