I recently paid to become copper member for an account. I paid only half of BTC to the shown address for my account. After some time it displays that I need to pay more to be a copper member. So i sent the remaining BTC to the same account and become the copper member. So my question is

• Is the address shown to sent BTC is specific to my account only, if so all bitcointalk accounts has a specific BTC address associated to it ?
• How they track that I have not paid full BTC to become a copper member ?
• Where all this payment code logic stays and how it functiions ?

I want to kow how all this works.
It will be helpful ,if anyone mention any links or any source about this payment working nature.