Acquisitive agency holding company MDC Partners is diversifying its holdings beyond conventional advertising agencies into what it calls "social commerce" with the acquisition of dotbox. Terms were not disclosed, but MDC, whose last big acquisition was independent media services shop R.J. Palmer, described dotbox as a firm that "provides brands with a full suite of service offerings across strategy, implementation and activation, from classic e-commerce to socially integrated campaigns and full omni-channel retail solutions."