Yes, but is it $100 billion's worth of hard work? I guess that's what the market gets to decide.

Edit: also half the problem is caused by assuming 1 billion users translates to anything meaningful. Apart from being an impressive number in its own right, what exactly does it mean? Facebook is free to use and helps satisfy basic human social desires in a digital way. Great but would they have 1 billion users if it wasn't free? No.

If I could distribute beer for free and and offered every male on the planet over the age of 18 a free keg, I'd probably have a billion takers.