How to track down the origin of a transaction

[david123]

Hi,
I have a basic question. I'm sure this must have been discussed many times before, but
I couldn't find anything. So maybe someone can just point me to the right topic..

Suppose, I want to find out where the transactions to one specific address come from. I do suspect
that they all come from one source, which is some kind of service provider, like a gambling site
or a pay-per-ad site or something like that. I tried out this taint analysis and related tag stuff on
blockchain.info, but I couldn't find much of a clue..

I understand that there will be many cases where it is just impossible to find out. But what would
be the straightforward procedure and tools..?