Meta

A shadowtalk idiom.

As a noun: A meta is a topic about the shadownet itself, the echo to which it is posted, or a user's ability to access the group. Also a discussion about shadowtalk, except on groups dedicated to that. Such topics are usually branched from relevant topics on a group.

As an adjective: Pretty, interesting, but ultimately useless. Implies that something takes far more time than it deserves, and could be a major distraction from work. Derived from the noun form. Note that "a meta" and "a meta topic" are therefore quite different things; though many metas are quite meta.