My nearly 70 year old mother, technophobe and risk averse to a fault (e.g., had much of her retirement portfolio since'09 out of equities), finally asked me the

My nearly 70 year old mother, technophobe and risk averse to a fault (e.g., had much of her retirement portfolio since'09 out of equities), finally asked me the other day if she should buy some Bitcoin. Yes, if cryptocurrencies prove to be a real revolution the way the Internet was, there's plenty of upside left. If not, though, I'm not sure there's too many greater fools left if my mother's almost there. As they say, you know it's time to sell when shoeshine boys give you stock tips...