Must-watch: Jeremy Grantham, the man who called the 2000 AND 2008 bubbles, just called Bitcoin "proof of unnecessary work, not worth a bucket of warm spit." You've heard pet rock. You've heard Ponzi. Bucket of warm spit is a new one. Every currency in history has been controlled by someone. Bitcoin is the first one that isn't. Fixed supply, no central bank, no printing press, no permission needed. That's not speculation. That's the point.(Lark Davis)