"One need only see what transpired with the iPod and its impact on CD purchases as well as other historical transformations such as digitizing records, Internet sales, online media, et cetera, for pre-existing protocol, " says Matt Lloyd, chief investment strategist of Advisors Asset Management.

FORBES: Magazine Article

Much of the talk at this week's conference was how major urban centers could work toward adhering to the Kyoto Protocol, the existing environmental treaty that sets targets for nations to reduce greenhouse gas concentrations.

CNN: Bill Clinton to cities: Act on climate

Many developing countries have been arguing for a "twin track" approach, whereby countries with existing targets under the Kyoto Protocol (all developed nations except the US) stay under that umbrella, with the US and major developing economies making their carbon pledges under a new protocol.

BBC: Copenhagen climate summit negotiations 'suspended'

They created new signs and remodelled existing ones, based on the European protocol of triangular signs to warn, circles for commands and rectangles for information.

BBC: The road sign as design classic