Is following possible with programming?

[BurtW]

Not only will most of us here not help you, we will be doing everything in our power to make it impossible for you to do this.

Seconded.  If you're trying to link people's transactions without their active consent and cooperation, then you're working directly against their interests.  Good people will be trying to stop you.

Good people will be trying to stop me?  

If you see from my frame of mind then, I'd say bad people will be trying to stop me. I'm just working on some hypothetical concepts here, dude. You might be amazed to know that I got flunked on C++ three times.  
You expect me to go against your community with these skills? I'm just being dreamer here. Chillax!

I think he meant good in the sense of "good at math and programming" or "better than you at math and programming" not good as in good and evil.

You do need to know that the idea of attaching identities to transactions is a direct attack on the concept of Bitcoin and in fact all public ledger systems.  You cannot have both the ledger and the identities be public.  Such a system would not ever be used by anybody.  Would you use a system where who you are and how much you have and exactly how and where you spend all your money is totally public?  I think not.  One or the other has to be private:  transactions and amounts are private but identities are public (current fiat money system) OR transactions and amounts are public but identities are private (Bitcoin and other public ledger systems).

[Tisko]

Wow, you guys replying are AMAZING. Impressed by the patience that many posters have here. 

[BitThink]

A proper way for a merchant to receive BTC payment is to generate an address for each customer. It's a standard way and helps a lot for tracking who pays how much automatically. You could generate a BTC address when people login in and store that in the DB.

Please use one public address approach only as donation address.

[BurtW]

Actually, if you believe as I do that Bitcoin should remain fungible money and not eventually be reduced to a mere collectible then you should never reuse an address for any reason.  Address reuse allows BTCIndia and others of his ilk to begin to and eventually attach identities to addresses.  This strikes at the very core of what Bitcoin is or will become.  In order to maintain and support the fungibility of Bitcoin:

Stop using vanity addresses
Always send change to a new address
Use a new address for each transaction
Even donations should be done through new addresses
All periodic payments should use BIP32
Coins should be mixed as often as possible, hopefully someday all transactions will be automatically mixed in every block
Avoid attaching identities to addresses