user80: You run bitcoin as a service on your local computer.  What happens if this computer is compromised?  A corrupt/failed hard drive or theft leads to the machine being lost and unrecoverable, and my bitcoin details (addresses etc) are gone.  Do my bitcoins disappear into the ether?
i.e. What happens to my bitcoins if my wallet file is compromised/lost?

user15: Yes.
This is because of the decentralized nature of Bitcoin. You are the master of your own private keys. With great freedom comes great responsibility.
You have to come up with your own precautions.

user38: The Bitcoins never disappear, but if you lose your wallet, then you lack the keys necessary to actually use those Bitcoins.  So although the coins do not disappear, they are effectively removed from the economy since you cannot spend them.  This is why it is important to backup your wallet.

user365: Your coins still exist, but your ability to use them is gone. No one knows this, as they still appear to be perfectly valid. And, in fact, if you ever recovered your wallet somehow (say you discovered a backup on a USB key somewhere), you could then spend them.

user4774: If a wallet file is truly lost with zero ability to recover it, then the coins it contained are lost forever.  Think of it as cash left in a burning house.  
Be sure to periodically backup your wallet.dat file.  It is best to also encrypt those backups lest they be compromised giving someone else access to your wallet.

80: <p>You run bitcoin as a service on your local computer.  What happens if this computer is compromised?  A corrupt/failed hard drive or theft leads to the machine being lost and unrecoverable, and my bitcoin details (addresses etc) are gone.  Do my bitcoins disappear into the ether?</p>

<p>i.e. What happens to my bitcoins if my wallet file is compromised/lost?</p>
 15: <p>Yes.</p>

<p>This is because of the decentralized nature of Bitcoin. You are the master of your own private keys. With great freedom comes great responsibility.</p>

<p>You have to come up with your own precautions.</p>
 38: <p>The Bitcoins never disappear, but if you lose your wallet, then you lack the keys necessary to actually use those Bitcoins.  So although the coins do not disappear, they are effectively removed from the economy since you cannot spend them.  This is why it is important to backup your wallet.</p>
 365: <p>Your coins still exist, but <em>your ability to use them</em> is gone. No one knows this, as they still appear to be perfectly valid. And, in fact, if you ever recovered your wallet somehow (say you discovered a backup on a USB key somewhere), you could then spend them.</p>
 4774: <p>If a wallet file is truly lost with zero ability to recover it, then the coins it contained are lost forever.  Think of it as cash left in a burning house.  </p>

<p>Be sure to periodically backup your wallet.dat file.  It is best to also encrypt those backups lest they be compromised giving someone else access to your wallet.</p>
