Cohomology of Banach algebras is a setting in which knowledge about the structure of a Banach algebra is obtained by classifying its actions on Banach spaces. For Banach subalgebras of B(X), the Banach algebra of bounded operators on a Banach space X, this task roughly amounts to a study of interdependence of factorization properties of linear operators and geometric structure of the underlying Banach space. In the talk we will describe the general ideas and give some recent developments.