Given the current issues on hacking and loss of credit card details, I would suggest the following as some sort of protection. Get yourself a second card (debit if possible) linked to a separate account, and use it solely for on-line and other potentially risky purchases. Either keep a minimum amount in the associated account, or else top it up before making a purchase. That way, if the card is compromised, your normal credit card is not affected and any losses will be minimal, particularly on a debit card where only the account balance is at risk.
