The call went out on Twitter: “For insane profits come and join the pump.” It was an invitation to a penny stock-style pump-and-dump scheme — only this one involved Bitcoin, the soaring, slightly scary virtual currency that has beckoned and bewildered people around the world. While such bid ’em up, sell ’em off scams are shut down in the financial markets all the time, this one and other frauds involving digital money have gone unchecked. The reason, in no small part: Government authorities do not agree on which laws apply to Bitcoin — or even on what Bitcoin is. The person behind the recent scheme, a trader known on ... (full story)