A statistically rough ( one sigma) estimate might be 75-100 million servers @ ~350-550 watts each.. Call it Forty Billion Watts or ~ 40 GW. Since silicon logic runs at three volts or so, and an Ampere is some ten to the eighteenth electrons a second, if the average chip runs at a Gigahertz , straightforward calculation reveals that some 50 grams of electrons in motion make up the Internet.
That, and many other interesting calculations, are explored in this quirky, if cynically eloquent written article by Russell Seitz. Like, the average human brains (rated at 20W) has about 6W of computing power at its disposal. Or that on average, a US home still needs four miles of copper wire to connect to the information grid. And that, to power those 50 grams of electrons that powers the Internet, we need 50 million horsepower.
An amusing take on the Internet – it is quite amazing to think that this substance-less (save two ounces) medium create real companies, wealth and growth to nations. While previously, you may have to own tonnes of ores, or a large energy-guzzling mining factory, or vast lands and plantations to create wealth. In this age, all you might need is just 2 horsepower and maybe 10 nano-grams of electrons.