System D is a slang phrase pirated from French-speaking Africa and the Caribbean. The French have a word that they often use to describe particularly effective and motivated people. They call them débrouillards. To say a man is a débrouillard is to tell people how resourceful and ingenious he is. The former French colonies have sculpted this word to their own social and economic reality. They say that inventive, self-starting, entrepreneurial merchants who are doing business on their own, without registering or being regulated by the bureaucracy and, for the most part, without paying taxes, are part of "l'economie de la débrouillardise." Or, sweetened for street use, "Systeme D." This essentially translates as the ingenuity economy, the economy of improvisation and self-reliance, the do-it-yourself, or DIY, economy.System D is the planetary unregulated black market, concentrated in the developing world. Excluding traditional criminal activities (robbery, illegal narcotics, extortion) but including small-scale entrepreneurial activities that don't bother with red tape or taxes or safety regulations, it employs up to 50% of the planet's work force (1.8 billion workers) and is estimated to be worth $10 trillion a year.
Oh, and the internet has done rather a lot to potentiate its growth. As is the case in conventional markets, the internet makes communication easier; this in turn tends to disintermediate supply chains, choking off rent-seeking and arbitrage except where local monopolies emerge.
(I'm blogging this because I think it's a useful reminder that, globally, the WEIRD is not the only way; and as nominal world GDP is around $64Tn, System D is already huge and growing bigger all the time — if it was a national economy, it would be the world's second-largest, after that of the USA. Also: the Greek black economy accounts for 25.4% of GDP (as of 2010). What are the implications if Greece defaults ...?)