Four out of ten YouTube views in the United States and one in four worldwide are now on mobile devices. YouTube now receives over a billion views a day on handheld screens. With the rapid rise in adoption of smartphones and tablets, online video is increasingly being viewed on smaller screens, a trend that is likely to continue.

The recent growth in mobile usage comes despite Apple dropping YouTube as a core application for its mobile devices. YouTube then released its own app, providing a similar experience across all mobile platforms, which it is able to monetize through advertising, tripling its mobile revenue in the past six months.

With YouTube TrueView, users can choose to skip ads after five seconds and advertisers only pay if they watch for at least 30 seconds or see the whole ad. This has enabled YouTube to provide keyword advertising against an increasing proportion of its user contributed videos.

Over half of smartphone users in the United States used the YouTube app in March 2013. Smartphones account for over 60% of mobile subscribers in the United States, rising to nearly 80% among those aged 25-34.

However, over 70% of YouTube traffic comes from outside the United States, with over a billion unique users visiting YouTube every month.

Ericsson forecasts that there will be 4.5 billion smartphone subscriptions by the end of 2018, with video expected to account for half of all mobile data traffic. That said, the majority of video viewing on handheld screens is likely to be in the home, over wireless networks with fast broadband access.

“I believe YouTube realizes that its future is all about mobile,” writes Mark Cuban, who began webcasting in 1995 and in 1999 sold to Yahoo! for an incredible $5.9 billion in shares. “Watching video on a mobile device is good enough,” he writes.

Indeed, watching video on a handheld touch screen is often a more immediate and rewarding experience than fumbling through menus on a big screen with a remote control. People may use their handheld screen to navigate and show video on another screen, but according to Mark Cuban that will remain a minority usage.

“I don’t think people perceive there is enough of an improvement in the viewing experience to tie up both their phones and their big screen TVs,” he writes. “It looks like YouTube users are satisfied with the mobile video viewing experience.”

YouTube still receives a relatively low volume of viewing compared to television in general, but it offers a single global platform that can reach a billion users, which is far more than any broadcast network.

Just over eight years since the first video was posted, over 100 hours of video are now uploaded to YouTube every minute and over 4 billion hours of video are watched each month.

The relative increase in viewing on handheld devices is not limited to YouTube. In the case of the BBC iPlayer, viewing on phones and tablets makes up 36% of requests for television programmes, up from 18% a year previously. Meanwhile, the number of requests from televisions or devices connected directly to them has fallen from 30% to 22%, despite an increasing number of internet-connected televisions and set-top boxes.

There were nearly 2 billion requests for television programmes through the BBC iPlayer in the year to May 2013 and over a quarter of them were viewed on tablets or mobile devices.