Analyzing Comcast-TWC's regulatory chances using HHI

So what are the chances that a combined Comcast (NASDAQ: CMCSA) and Time Warner Cable (NYSE: TWC) pass the antitrust portion of the merger's regulatory review? TechDirt provides a fairly practical framework using the Herfindahl-Hirschman Index (HHI), the essential tool used in antitrust law to determine market concentration. The rather compelling analysis can be read here.