In the endless search to extract value from telco networks, PCCW's Viu TV is already clocking up some promising numbers.

Launched just 18 months ago, the PCCW Ltd. (NYSE: PCW; Hong Kong: 0008) video service, which specializes in Asian content, has signed up 6 million active mobile users, each watching an average of one and half hours a day. (See When a Telco Goes OTT.)

Crucially for Viu's 20 telco partners, the OTT service is driving data consumption and customer acquisition as well.

Helen Sou, senior vice president of PCCW Media, says for operators offering Viu mobile data consumption has risen by as much as two and a half times.

Speaking at Broadband Forum Asia this week, she cited one major market where WiFi typically accounts for three quarters of wireless data consumption. For customers using Viu, however, this was reversed -- mobile data accounted for 75% and WiFi the remainder.

People are also upgrading their data plans. Those who didn't have data plans are now buying them, and those on bottom-end plans are migrating to more expensive deals or, in some cases, upgrading their phones.

The pattern shows up even for Viu's WiFi partners, where users on hourly passes are upgrading to weekly or monthly ones.

The impact is strong and consistent, Sou says. "It's happening in most of our markets. It's also growing very fast."

She attributes this to the stickiness of the service, which has also proved quite consistent.

"They come in very often and every time they consume for quite a long while -- more than one video at a time. That's a very important metric to us."

Want to know more about the impact of web services on the pay-TV sector? Check out our dedicated OTT services content channel here on Light Reading.

Most Viu content is long form, says Sou, with subscribers watching 12 videos per week. Consumption is steadily rising as well -- the average daily viewing time has risen from 1.2 hours earlier this year to 1.6 hours today.

Sou also says that users are the kind advertisers love -- millennials with high discretionary incomes and receptive to digital ads.

The underlying factor is the strong content, Sou says.

Viu, which is offered so far in 14 markets in Southeast Asia, India and the Middle East, includes Chinese and Japanese content and a deep bench of the hugely popular South Korean TV dramas. As well as subtitling these in local languages, Viu carries locally produced content for viewers in southeast Asia and India.

— Robert Clark, contributing editor, special to Light Reading