It is probably fair to say that most Linux developers never end up using chroot()
in an application. This system call puts the calling process into a new
view of the filesystem, with the passed-in directory as the root
directory. It can be used to isolate a process from the bulk of the
filesystem, though its security benefits are somewhat limited. Calling
chroot() is a privileged operation but, if Mickaël Salaün has his
way with this patch
set, that will not be true for much longer, in some situations at
least.

Source: LWN.net – [$] Unprivileged chroot()