Facebook has a billion users in a single day, says Mark Zuckerberg Aug30 by Joseph Saraceno For the first time over a billion people used Facebook on a single day, according to company founder Mark Zuckerberg. The “milestone” was reached on Monday, when “1 in 7 people on Earth used Facebook to connect with their friends and family”, he said in a post. MORE Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on Google+ (Opens in new window) Related