TVii also has a traditional channel guide and will recommend shows you might like based on favorite shows, networks and movies that you enter. Different users can have different profiles, and parental controls are included.
Nintendo hopes the service boosts sales of its console. About 425,000 Wii U units were sold in the first seven days on sale. That's faster than the rollout of Microsoft Corp.'s Xbox 360 and Sony Corp.'s PlayStation 3 when they debuted in November 2005 and November 2006 respectively, although initial sales are often constrained by supply, not demand.
Analyst Michael Pachter of Wedbush Securities said the TVii service puts Nintendo a step ahead of its competitors, but he expects Microsoft to close the gap next year with a next-generation Xbox that includes a TV tuner. Microsoft hasn't announced such a device.
"It gives them a head start. I think they should be congratulated on making this a truly multimedia device," Pachter said. "I don't think that advantage is going to last very long."
Nintendo has also added social networking features to its service. A team of curators will watch the top 100 shows on live TV and post details and a screenshot of important events, such as "a great shot in a basketball game or an unexpected twist in 'Mad Men,' " according to Zach Fountain, director of network business for Nintendo of America.
Users can then comment on these moments and have those posts show up on Nintendo's Miiverse network, as well as Facebook and Twitter if they choose. Users that express emotions could wind up with a sad or happy-looking Mii avatar.
Live sporting events such as pro or college football will also be accompanied by scores and play-by-play summaries on the GamePad's screen.
One problem with the service could be the GamePad's battery life. Nintendo says the controller can be used three to five hours depending on activity and screen brightness before it needs to be charged. But TV ratings agency The Nielsen Co. says the average American watches nearly five hours of TV per day. Heavy users may need to keep the controller plugged in to a wall socket, or buy a $25 battery pack that its maker, Nyko, promises will double the battery life.