Leyendo en Google Blogoscoped encontré este post que habla de la cuando es 1gb de capacidad, aqui vá:

How Much Is 1 Gigabyte?
We know Gmail allows us to store 1 gigabyte of emails. But how much is 1 gigabyte really? The question might seem trivial to answer: just google it. But you will get a different answer depending on who you ask.

Google in their Gmail dialog says it’s 1,000 megabytes (or 1,000,000,000 bytes). That’s the truth according to International System of Units. But as my previous Gmail stress test shows, Google allows us to store more than 1,000 megabyte.

Other people think 1 gigabyte is 1,024 megabytes (or 1,073,741,824 bytes). Even the Google Calculator will tell you one gigabyte = 1024 megabytes when you enter «how many megabytes in one gigabyte». That’s what About.com’s «File Sizes Explained» says too.

Because of above irregularity in definition, we also end up in a messy place talking about a terabyte.
A terabyte could be 1,000,000,000,000 or 1,099,511,627,776 bytes. I could go on with the petabyte but will spare you even longer numbers. And of course it doesn’t stop there either: we can continue with the exabyte, the zebibyte (which is 1024 times an exbibyte), or the yottabyte. OK, just for fun let’s write out the yottabyte:

1,000,000,000,000,000,000,000,000 bytes.

(Compare that to the thoughts a human thinks per day, around 40,000, and you realize it must be an awfully big number.)

So let’s start at the beginning. A byte is a small unit and should be well-defined – a byte is eight bits, right? It may be today. When Werner Buchholz coined the term in 1956, it could describe one to six bits. That’s why an eight-bit byte is also called octet in formal contexts. (Half of a byte, by the way, is a nibble, which is also called semioctet.)

And a bit? That’s the information atom, the smallest unit the computing revolution could think of. It’s geek jargon for binary digit and denotes the smallest unit of storage. It’s what computers perform calculations on (unless we are talking about quantum computers, which manipulate qubits.)

And finally, it’s pretty clear what a bit means.

I saw an interesting illustration once. There was a king, and he had servants to serve him meals. Because it was quite a walk from the kitchen, the king – sitting on his large table – decided to raise his left arm when he was hungry. A single arm raised once therefore would hold the information «I’m hungry», but the king could not specify the type of dish he wanted. After some days he was bored by the same food, so he started to use both arms. Now he could communicate four different wishes to the servants – no arm means «not hungry», left arm means «potatoes», right arm «noodles», left and right together «dessert».
So two arms are two bit, and two bit allow us to count four numbers in binary (from zero to three: 00, 01, 10, 11).

Now after all this confusion, how much is 1 gigabyte? Well, if people ask you just tell them: it’s a lot.