What is the Keychain?
The Keychain is a security feature in the iMac machines that allows multiple users access to the same computer. Each user can make their own computer settings, etc. This feature is not very useful at KMS, so it is not used. It is buggy, and prone to abuse by unknowing, prying students. Perhaps sometime in the 21st century, someone will figure out a meaningful way to use the Keychain feature, but for now, it is to be avoided.