There are 70 million tablet users in the U.S. This VivaKI study shares insights into what they do on them every day.

Editor’s note: “Mobile Matters” is our ongoing series where we look at top issues, challenges, and opportunities in the fast-moving world of mobile marketing. We recently shared findings from a major tablet study by VivaKI that revealed the three most effective ad formats for the device. Here we highlight the study’s insights into the online habits of tablet users, which marketers can use to connect with them.

There are 70 million tablet users in the U.S, according to a recent study by VivaKI, and they spend an average of 90 minutes a day on their devices. The rapid growth of tablet users has triggered a “seismic shift” in consumer behavior that marketers should understand and leverage, says the study, and it shares insights into their daily activities on their devices.

The 14-month study collected data from 26 companies (including Yahoo!) and 20 million consumers, or one-third of the total tablet market in the U.S. Here are some highlights on tablet usage from the study.

Web browsing and email leads daily tablet activities

What do tablet users like to do most with their devices? Five of their top seven activities focus on consuming various forms of online media, which gives marketers insights into where to connect with them on the Web.

• 93% use their tablets to browse the Web
• 86% use them for email
• 70% use them to check the news

A day in the life of a tablet user

What are the main tablet activities at any given point in the day? The study shows tablet usage patterns over a typical 24-hour period, which helps marketers pinpoint the times they’re most likely to connect with their target tablet audiences. Here’s a look at what tablet users do on their daily tablet rounds.

6-9 a.m.: Tablet use rises steadily with users checking email, weather, social media, and the news.

9 a.m.-noon: Activity level dips; top uses are local searches and navigation.

Noon-4 p.m.: Activity picks up as stay at home moms and caretakers help kids with schoolwork and keep them entertained.

6 p.m.-8 p.m.: Family use continues to rise, with parents using tablets with kids for homework and fun.

8 p.m.-11 p.m.: Prime time for tablet users as they wind down from work. In fact, tablet traffic outdoes smartphone and PC traffic in this time period. Top tablet activities are entertainment and social media.

• Gaming and multi-screen multi-tasking is highest
• Traffic on news sites peaks at 10 p.m.
• Shopping peaks at 9 p.m.

11 p.m.-6 a.m.: Tablet activity slows down, but 12% of tablets are used at some point during this time.