In terms of population, that is:
THE world's largest social network announced that it had reached 500m members on Wednesday July 21st. If Facebook were a physical nation, it would now be the third-most populous on earth. And if the service continues to grow as rapidly as in the three months to July, it will reach one billion in about 15 months—almost the size of India. Not least because of its gigantic population, some observers have started to talk of Facebook in terms of a country. “[It] is a device that allows people to get together and control their own destiny, much like our nation-state,” says David Post, a law professor at Temple University, Philadelphia. For more on social networks and statehood see article.
Seems like Facebook represents a largely untapped economic market for some enterprising entrepreneurs. (Have you ever bought anything on Facebook?)
This data also makes me wonder how large Facebook’s population would be if it wasn’t blocked in China? Maybe not as much as I might think. Privacy concerns seem to have restricted its growth in Japan and South Korea.
Here is a breakdown of Facebook users by country.