Earlier Windows versions had EFS (Encrypting File System), which was a bit infamous for eating user data in the hands of inexperienced users. The reason is that EFS is tied to the Windows user account. Thus if the Windows installation is lost, then a EFS formatted external or secondary drive can often not be read anymore.
Windows 8 introduces "Bitlocker to Go", a variant of the updated Bitlocker encryption in Windows 8, intended for removable drives.
'Regular' Bitlocker is usually tied to the computer somehow -- either to a Trusted Platform Module (TPM) chip, or to a USB key with a certificate on it, or to a Smartcard.
Is Bitlocker to Go tied to the computer or Windows account in any way, or is the encryption exclusively derived from the Bitlocker to Go volume password? In other words, if the original host Windows installation crashes and is lost, can a Bitlocker to Go drive then reliably be unlocked on another Windows 8 installation, given that the volume password is known?