technique called "temporal aggregation" that is highly refined and is used to correlate networked transactions. The wallet, that contains EVERY address of every bitcoin user and a record of EVERY TRANSACTION makes it even easier.
Using temporal analysis on the blockchain augmented by realtime monitoring of bitcoin transactions on Tor nodes, a Scottish University, funded by Citicorp, gleaned login id's, passwords and even home addresses.
Your disdain of unpleasantness is causing you to deny the empirical evidence.
The US Military, the western intelligence agencies, and the Banksters of the West have the largest, highest paid armies of networked system and financial transaction system developers in the world! And they have not been sitting by the past few years ignoring bitcoin. They are on top of it. And it's not like those groups have not been TOTALLY FREE to set up mining ops, to purchase bitcoins, to bribe the owners of MtGox under threat of prosecution or worse if they don't play along, and to game the system since day one.
~wobbles but doesn't fall down~