I've been thinking a bit about post R1 features and I see that there is a clear motivation to eventually add multi-user capabilities to Haiku and I feel that this is a mistake. Haiku should remain a single user OS. Personal computers are and should be personal, that is, they should cater to a single individual. Adding additional users adds additional complexity which makes the entire system harder to use and more abstract. Families that share a computer need not have multiple accounts. It's a niche case which is better served through individual account services. By not having multiple user accounts you don't have to worry about if an application is available for a single user or all users on the system, all applications are available. Same goes for shared resources such as music. By not having user accounts you are allowed to use the computer anonymously, you don't have to first identify yourself, this is a really important benefit. What is needed is privilege separation ala sandboxing. Applications should only be allows to read and write from specific locations such as their own settings files. Applications should need to special privileges to write to shared areas like adding and the like. The problem of security is orthogonal to multi-user, one should not influence the decision to utilize, or not utilize the other.