the heritage of SmartOS is this:
Kernel, core userland, OS virtualization, filesystem, network stack, etc. == from IllumOS (with a SmartOS-specific Linux-KVM port), which itself is an open source continuation of OpenSolaris after Oracle shut off the source code tap;
High-level userland (web servers, shells, databases, etc.) == from NetBSD, with a fork of pkgsrc and build system fixes and such