blockexplorer 可以看到任何一个 BTC 收款地址上发生过的所有交易

这代表着泄密么？如果你曾经公开过一个address，那么和这个地址有关的所有来往都是公开的咯？（尽管我们假设所有对方交易地址都是保持私闭的）

交易必定是可追踪的，所谓匿名，是不让addrss对应到一个具体的人。这有很多办法可以实现。而且还可以使用 mybitcoin.com 这种服务来实现和人的彻底隔离。

https://en.bitcoin.it/w/index.php?title=Special%3ASearch&search=anonymity

这里面讨论了这些问题：

You might be thinking that this attack is not feasible. But consider this case:
You live in China and want to buy a "real" newspaper for Bitcoins.
You join the Bitcoin forum and use your address as a signature. Since you are very helpful, you manage to get 30 BTC after a few months.
Unfortunately, you choose poorly in who you buy the newspaper from: you've chosen a government agent! Maybe you are under the mistaken impression that Bitcoin is perfectly anonymous.
The government agent looks at the block chain and Googles (or Baidus) every address in it. He finds your address in your signature on the Bitcoin forum. You've left enough personal information in your posts to be identified, so you are now scheduled to be "reeducated".
You need to protect yourself from both forward attacks (getting something that identifies you using coins that you got with methods that must remain secret, like the scammer example) and reverse attacks (getting something that must remain secret using coins that identify you, like the newspaper example).