YouTube reaches one billion monthly users 21 March 2013 Last updated at 09:11 YouTube, the video sharing site owned by Google, has announced it has passed one billion regular users. Announcing the milestone on its blog, the site said a recent growth in smartphones had helped boost the numbers visiting the site every month. YouTube's popularity provides Google with a lucrative channel through which to sell advertising, alongside its core search business. 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. 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. The BBC also has a presence on YouTube, with a number of different channels. Some are run by BBC Worldwide, the commercial arm of the corporation. 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.