Although steps can be taken to make tracking of bitcoins very difficult, for the most part they far from provide the anonymity that most believe.
From New Bitcoin World:
Take for example Bitcoin's most advertised feature, its supposed anonymity. Everyone from the mainstream media to Wikileaks to the now-disbanded hacker collective LulzSec has trumpeted Bitcoin as "anonymous." But the truth is that researchers have long since proven it's anything but, since every bitcoin transaction appears on a public ledger distributed to everyone in the network (called the "block chain"), tracking bitcoins back to individuals is often trivial.Efforts are being made to create software to make tracking more difficult, however, in the eyes of government this will be viewed as a further step toward making bitcoins a money laundering machine. From NBW:
. Developed by cryptographers at Johns Hopkins University, Zerocoin is being proposed as a kind of "plugin" for Bitcoin clients that promises true anonymity by essentially giving the Bitcoin network its own built-in money laundering system[...]