I ran one for quite a while back in the netbook days - snowleopard worked quite well on the first Atom eeepc. Back then macos was a bit of a revelation - coming from Windows or Linux where the first thing you did after installing the OS was spend a few hours tweaking things, there was nothing to do and it just ran.

Eventually I went back to debian linux after a main disk failure and kept the machine going a few years longer by progressively lightening the software load, from gnome -> xfce -> lxde, but the time came when it was just too slow to browse any more, and it had to be retired.