Connected TVs are becoming mainstream, with over half of the US population expected to watch streaming content on them by 2016, and more than 60% doing so by 2019. But the nuances of connected TV use are still evolving, with the devices used to access content different from what one might expect and viewing habits more similar to those of linear TV, as explored in a new eMarketer report, “US Connected TV Usage: Digital Content Gives the ‘First Screen’ New Life.”

eMarketer defines connected TVs as TV sets connected to the internet through built-in internet capability or through another device such as a Blu-ray players, game consoles or set-top boxes. US connected TV viewers will top 200 million by 2019, up from around 140 million this year. Growth rates will slow during the forecast period as widening adoption leaves a shrinking population of non-users.

Because connected TV is, by its nature, a household phenomenon more than a personal one, household penetration is an important metric. In 2015, the US penetration rate will jump to 56.6% from 46.3% a year earlier, and growth will continue. By 2019, US household penetration will reach 78.1%, with 97.3 million households on board.

Consumers tend to use the same video apps on their connected TVs as on their mobile devices, and they typically bounce back and forth among all available screens. However, viewing habits for connected TV more closely resemble linear TV than other digital platforms.

A Q2 2015 Tremor Video study found that primetime was the peak time period for connected TV ad requests on its platform. The 3-hour period from 8pm through 11pm accounted for 22% of daily ad requests around connected TV viewing, compared with 16.7% for tablets, 13.8% for smartphones and 12.9% for desktop. Although activity on Tremor’s network doesn’t necessarily reflect the industry as a whole, the company’s findings indicate that consumers perceive the connected TV experience as a logical extension of linear viewing.

Nielsen data confirms these findings. The company found that the share of average US audience on connected TV devices peaked during primetime in the year leading up to May 2015, mirroring long-established patterns of linear TV viewing.

eMarketer corporate subscription clients can view the full report here.