What the Murdoch paper fails to say is that what security you need depends on the impact of
breaking the scheme. If someone steals a LWN cookie or WSJ cookie the marginal cost of
shipping the bits to them too is presumably minimal.
If you are thinking of online banking, stock trading or another system where the impact can be
large then you probably want something stronger than what is proposed. It is easy to ensure
that cookies only work once if you have a database table that maps cookie values to user
Some banks think that things like SecurID's tokens are worth the money.
FYI you can throw money at the SSL performance problem. An outfit called nCipher sells gigabit
ethernet adapters with both TCP and SSL done on the hardware. Disclaimer: nCipher will be
employing me in the near future :-)