Clustered vs. Isolated Star Formation
  I argue that star formation is controlled by supersonic turbulence, drawing for support on a number of 3D hydrodynamical and MHD simulations as well as theoretical arguments. Clustered star formation appears to be a natural result of a lack of turbulent support, while isolated star formation is a signpost of global turbulent support. 
Mordecai-Mark Mac Low (Amer. Mus. of Natural Hist., NY)