> Linux is still in the stone age when it comes to tagging. Common Linux filesystems (including ext4 & ZFS) support extended attributes, but I'm not aware of any Linux distro or file manager that includes tagging features based on them (or embedded metadata, for that matter).

KDE has decent support of tags in extended attributes. Tags are shown and can be edited in Dolphin (file manager), gets indexed by baloo. This is far from stone age as author claims!