Everything that is old is new again. For full disclosure i went from support Linux/Solaris (sysadmin) to mainframe middleware (CICS/WebSphere app server).
Yeah. Back when I started as a sysadmin chroot jails with bind, qmail etc were all the rage.
I've seen them used in good and bad ways, but mostly the former. It's good to see something that actually solves real problems coming back in to use again. Added bonus, it's an extremely mature (from a tech perspective) way of doing things. Chroot jails have been around for decades.
