YouTube has announced that it has more than 1 billion unique users every month, putting the video sharing site in the same club as Facebook, which reached the same figure last October.
The Google-owned site attributed much of the recent growth to a boom in smartphone use.
With one billion monthly users, it poses a challenge to Facebook as the internet's largest social network. Facebook reached a billion users in October last year.
"Nearly one out of every two people on the Internet visits YouTube," the company said in its statement.
It was keen to stress the business potential of such a large audience.
"Tens of thousands of partners have created channels that have found and built businesses for passionate, engaged audiences. Advertisers have taken notice," it said, saying that the top 100 brands listed by trade magazine Advertising Age were now running campaigns on YouTube.
YouTube has attributed its large growth to Generation C, a term coined by metrics firm Nielsen to describe American aged 18 and 34. “Born sometime between the launch of the VCR and the commercialization of the Internet, Americans 18-34 are redefining media consumption with their unique embrace of all things digital,” Nielsen said in an early 2012 study.
During 2012, the number of Generation C viewers watching YouTube on mobile devices equaled YouTube’s desktop viewership, according to Google. Around 67 percent of Generation C also watch YouTube on more than one device, compared to 53 percent of the rest of YouTube’s viewership.
YouTube was launched in 2005 and bought by Google in 2006. It paid $1.76bn (£1.16bn) for the site, which at the time had an estimated 30-40 million users world wide.
The site was launched in California by three former PayPal employees.
The first video uploaded was by co-founder Jawed Karim and titled Me at the Zoo.