Don’t use your real email account to register. These are websites that accept your bitcoins and send you back different bitcoins that have no connection to your previous activities. To make the transaction record harder to follow, mixing services will generally send the «clean» coins back to you in multiple transfers over a staggered time period. Bitcoins may well take off in the real-world in the future, but then again what would stop another cryptocurrency from emerging and defeating the Bitcoin, especially if it was indeed better? Electrum is an excellent bitcoin wallet that comes preinstalled on Tails Linux. Alot fo great info though! The extra device will also help you detect if malware that compromises your anonymity somehow made it on to your computer.