Ontolog Forum
TagCommons
TagCommons is a place and a process to create ways to share and interoperate over tagging data. The initiative is started by Tom Gruber, who, along with members of this community, believe that the world should have the benefits of rich social tagging across applications, communities, and spaces.
The goal of this effort is to specify an agreement, at least an ontology and possibly a bridge to symbol-level formats, that specifies a common semantics and possible means for sharing or computing over tag data from heterogeneous, independently developed sources.