One billion people use Facebook in just one day — making it far bigger than most countries, and easily the most used technology product on Earth.

Mark Zuckerberg announced that for the first time, the site had passed the milestone number that meant that one in seven people on Earth used the site.

"We just passed an important milestone,” Zuckerberg wrote in a post on his personal Facebook. “For the first time ever, one billion people used Facebook in a single day.”

That number means that on Monday, Facebook was almost the place with the most people on it in the world, after China and India.

Zuckerberg said Facebook was connecting communities globally and he is "proud" of the company's success.

He wrote: "Our community stands for giving every person a voice, for promoting understanding and for including everyone in the opportunities of our modern world.