1) Used to differentiate individual tendencies within the anarchist movement.
2) Used by doctrines not related to anarchism that wish to be interpreted as such.
3) A prefix used to mock doctrines unrelated to anarchism that claim to be anarchists
Traditionally used to differentiate coercive Statist forms (authoritarian) of socialism from cooperative anarchist forms (libertarian). Adopted by the right-wing in the early 1900s to describe an extremist capitalist philosophy, who now try claim to have exclusive use of the term and ignore its roots.
While the real libertarians try to destroy all forms of domination, control and power, the other libertarians are plotting how to get it.