With data provided by users, Facebook knows a lot about non-users.

There is such a thing as a shadow profile. It is a shame that Zuckerberg denies its existence.

I resisted to create a Facebook account, but five years ago I did it. Many people had sent me invitations, and it looks like that with the information other users provided, Facebook correctly guessed many things about me. It did not asked my my home town: it asked me to confirm their guess. Same for high school, university, occupation, place of work, etc.

I do not know if Facebook "knew" all this about me or was guessing based on data provided by other people. Facebook knew that a large portion of people that invited me had studied on a particular high school, and other worked for a particular company. Anyway, my "shadow profile" was alive and well when I first met him.

Too bad I am deleting my Facebook account in a couple of weeks.

Some years ago, you could find thousands of books on Amazon about "Peak oil". The basic idea: Cheap oil sources are increasingly harder to find and we would have reached that point around 2010, when the price of an oil barrel passed the US$ 100 mark, and stayed there for good. Soon we would face wars for oil, the decline of the western civilization, riots on the streets, or all this together.

The demand for oil in China has decreased, and now the price of an oil barrel is around US$ 50. Everyone now is talking about "peak demand": oil consumption in OECD countries is almost flat for the last ten years, and the major source of growth comes from China.

Oil consumption is on the highest levels of human history, but with little change for the last decade. Meanwhile, the potential of growth of an important renewable source became scarce for the last couple decades: hydropower. It will take some time for us to actually see a decrease on consumption of oil and coal, as other renewables increase their share on the world energy consumption.

I agreee that Bitcoin is not a currency, as the transaction costs are far too high. On monetary theory terms, Bitcoin is not M1, but M2 or even M3.

But pay atention that there *is* a market for "cryptocurrencies". Some people want to make economic transactions completely outside the banking system. Currently they are on a "cash only" basis, but they might want to go eletronic with Bitcoin or any other "cryptocurrency".

But how big is this shadow economy? Nobody knows for sure. Nobody knows how fast they will adopt cryptocurrencies, or if it will be Bitcoin or something else.

Some countries are toying with the idea of eliminating cash to reduce money laundring and tax evasion (even the European Bank will stop issuing $ 500 notes), and that might take some people to cryptocurrencies. Once everyone that wants a cryptocurrency has migrated to that, their price should stabilize.

ESR is adopted by Eric himself, in his e-mail (esr@snark.thyrsus.com) and his personal home page (http://www.catb.org/~esr/).