"For the long term investor, cleantech is one of the best sector plays out there. And the best way to play a sector is with a low-cost ETF. This guide will review all 16 cleantech ETFs traded in the US, and offer investors the information they need to add a slice of long term growth to their portfolio. Not all cleantech ETFs are made alike, and we'll show you which funds are the best bets for future returns:"

"6: The argument for free trade comes from Ricardo's "comparative advantage" -- a clever textbook exercise, but irrelevant to the real world since it assumes constant costs. In reality, either you produce manufactured goods, in which your costs go down as you make more, or you sell off commodities, in which case your costs go up as you make more. With the former, it takes time for local industry to build up the advantage (requiring protectionism). With the latter, you end up like Mongolia, which opened up its animal husbandry market, swelling herd sizes, turning grass into permanent desert, and killing off the entire market. With no other exports, such a country is in big trouble. Ricardo was wrong: diversification, not specialization, is the way to develop -- and how every successful country has. Unfortunately, we've forced this broken system on most of the world....