Be File System (BFS), the metadata driven filesystem of BeOS that provided attribute queries, metadata editing and dynamic folders integrated into the desktop as part of Tracker, the file manager.

Chandler, a personal information manager

Dublin Core, a set of general terms for annotating web resources with metadata

Haystack, an information client developed at MIT

NEPOMUK, a specification for a social semantic desktop framework

Tabbles, a desktop tagging tool for files, emails and bookmarks

WinFS, a data storage and management system based on relational databases, developed by Microsoft

zeitgeist (framework)

image semantic desktop

define semantic desktop

wikipedia semantic desktop

weblio semantic desktop

kotobank semantic desktop

jisho semantic desktop