NEW YORK: Online video penetration will reach 60% of the US population by 2015 after passing the 50% mark this year, a new forecast has suggested.

Esimates from eMarketer suggest that video content accessed via mobile, as well as desktop and laptop PCs, was becoming a "mass-market pursuit". The research firm classifies an online video viewer as someone who watches the content at least monthly.

Penetration of online video viewing among US web users, rather than the general population, will rise from 65% to 76% between 2010 and 2015, with the annual growth rate of viewer numbers averaging 6.1%.

In good news for advertisers, eMarketer said that premium, long-form content, rather than short-form user-uploaded videos, was becoming an increasingly important driver of growth.

According to the research, the proportion of online video viewers watching streamed TV shows online each month would rise from 49% in 2011 to almost 63% in four years time.

Mobile is set for still more explosive growth, with penetration of online video viewers rising from 28.5% to 40% over the same period. Among the general population, this increase will be from 14% to 24%.

Paul Verna, a senior analyst at eMarketer, said that the growth was partly explained by online videos going mainstream, spreading from young adult early adopters to other age cohorts.

"Audience growth .... will be more pronounced among preteen children, older boomers and seniors," he said. "These groups have traditionally lagged teens and younger adults in their video viewing activity, but the gaps will start to close as the market matures.

"This will give marketers opportunities to take advantage of growth pockets among viewers at either end of the age spectrum."

Data sourced from eMarketer; additional content by Warc staff