The term is pseudonymous - the list of all transactions is available for anyone to look at but in theory you can't link bitcoin addresses to people. However, i

The term is pseudonymous - the list of all transactions is available for anyone to look at but in theory you can't link bitcoin addresses to people. However, in practice, most people buy bitcoins via a method that requires ID, which links their ID to one of their addresses. Multiple addresses can then be linked together by cluster analysis based on usage patterns