While there are industries where it makes sense to allow duopolies or even monopolies to obtain economies of scale and network effects computer operating systems and electric utilities might be two examples the tradeoff usually is that they must accept closer government regulation to prevent price-gouging and other abuses.

FORBES: If AT&T/T-Mobile Merger Would Raise Prices, Why'd Sprint Stock Jump?

The scale, scope and effects are all enormous.

CNN: Your e-mails: 'Clean up our wetlands'

Of course as cities get larger and larger, the challenge of dealing with mega-scale, overcoming its dehumanising effects and avoiding over-building becomes a central occupation.

BBC: Viewpoint: What makes an ideal city?