  It is widely accepted in the astrophysical community that the event horizon
plays crucial role in the Blandford-Znajek mechanism of extraction of
rotational energy of black holes. In fact, this view is a quintessence of the
Membrane Paradigm of black holes which suggests that the event horizon, or
rather the so-called stretched horizon, is similar to a rotating conducting
sphere of finite resistivity. In this paper we argue that this interpretation
is rather misleading and the proper explanation of the Blandford-Znajek
mechanism has to be sought in the properties of the ergospheric region of black
holes.
