Re: What a load of old virginia
USB devices are supposed to negotiate the current they draw using the data lines before they draw it, but old phone chargers and things like USB fans don't do that, they just send/draw 500mA.
Using negotiation with data lines hopefully manages to make a modern phone or tablet avoid drawing more than the charger sends or a USB port's fuse on a computer.
"Hopefully" because the voltages on the data lines for higher currents aren't very standardised yet. If you were to use, say, a Samsung 2A charger for an iPhone or iPad then it might have a funny turn or it might just charge slowly at 500mA (I've not tested it).
Biting the hand that feeds IT
