It seems like this is a boom for law enforcement. One of the fundamental aspects of bitcoin is that every transaction is recorded and publicly view able. In order to anonomize your currency you bassicly need to go through a mixing service, which takes bitcoins from a pool of users, and redistributes them back to the same users, but at new accounts, so it would be 'impossible' for someone to follow the money using only the blockchain.<p>There are two ways around the impossibility. One is to do statistical analysys to try and infer which two accounts are the same person. If you reguarly use the same service, this would likely be quite doable.<p>The other way around this is to compromise the mixing service (either hacking, or with a warrent).<p>There is currently research being done to make bitcoin properly annonomous [1]<p>[1] <a href="http://zerocoin.org/" rel="nofollow">http://zerocoin.org/</a>