Many people regularly use USB flash drives these days as they make life a lot easier: you can keep your favorite movies, business information, or valuable photos right over here in your pocket. But what if we say that a USB stick gets heavier when it's full? How about the claim that all information has a physical weight? Can't you imagine? Let's try to consider it in terms of science and make detailed calculations to find the answer.
Yes, because it uses electrons to record data.
It's roughly 0.01 trillionth of a gram! Yes, it sounds so little that it's hard to imagine, but it's true.
Calculations showed that it's less than one gram!
No, the brain mass of a genius is no different from the brain of a less intelligent person.
Someone may wonder what the flash drive mechanisms have to do with the information weight. But we need to learn how the drive works to have a full understanding.
So a flash drive consists of billions of floating-gate transistors. And this floating gate is where all information is stored. But it's not images, movies, or letters we are used to. No way. Here we deal with good old-fashioned binary coding. Meaning, all information is based on a coding system represented by "0" and "1". All the gate sides are covered with a dielectric material so that it can hold an input electrical charge and prevent occasional new ones. 
This is where the data storage mechanism comes from. If there is data on the gate, the computer perceives it as 1. If no information is recorded there, it will be 0. Thus, we have each gate storing no more than 1 bit of information. With eight gates, we could record the whole byte. Not that much, right? But we know that today's standard 8–32 GB flash drive is able to store billions of bytes! Can this amount make a distinct difference in the storage device weight? Let's calculate!
Let's take a quite large flash drive of 32 gigabytes for clarity—you can find it on the shelves of any shop today. For easy understanding, let it be 32 GB capacity, even though experienced users know it actually holds less amount information.
But compare the weight of an empty and a chock-full drive, and you won't see any difference, even with the latest and most sensitive scales. So we have to calculate the difference exclusively theoretically based on complicated math.
It's difficult to establish the exact number of electrons on the floating gate as different manufacturers give different data. On average, it's 14–40 thousand. Let's take the arithmetic mean of about 25 thousand. However, not all of them have weight as only some of the bits contain information 1, while the rest are 0 and thus weigh nothing. Let's think their number is roughly the same—anyway, the error is very tiny, if at all. A 32 GB flash drive totals 256 trillion bits.
As you may know from high school physics, the mass of an uncharged electron is 9.1 × 10−31 kg. Then we multiply the number of electrons on each floating gate, the total number of gates, and the mass of the electron, and get a resulting mass of... 3 trillionths of a gram.
Well, yes, not that much. Now you can see why even the most accurate scales fail to determine the difference in weight between an empty and a full flash drive. So we've proved the existence of this difference—at least purely theoretically - and this is already something!
After all, a flash drive is nothing! But if we take the whole Internet, we will for sure get a much more considerable weight, won’t we? According to the latest data, the total volume of all information uploaded to the World Wide Web is about 10 zettabytes (the number is growing rapidly), while 1 zettabyte contains a trillion gigabytes —the number is pretty serious.
Now imagine a 10 ZB USB flash drive capable of storing all the information from the Internet. By simple calculations, we find out that all the information ever made available to humanity in multiple languages and republished on thousands of sites weighs only one gram!
Moreover, modern technologies are used today for storing data, and servers do not use flash drives at all but hard drives, the principle of storing information which is completely different. So the weight of all this information does not reach a single gram. Not that impressive, is it? However, one lifetime isn't enough to watch, listen to, and read all this content! Then again, even if someone did, their brain would not get heavier in any way.
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