you must be thinking of the original filevault that encrypted each user's home directory separately. filevault 2 in lion is true full-disk encryption, and the

you must be thinking of the original filevault that encrypted each user's home directory separately. filevault 2 in lion is true full-disk encryption, and the passphrase must be entered at boot. once it is decrypted, no application should even be able to detect (or rather, care about) the presence of encryption.