Amazon will earn $9.85 billion in net US digital ad revenues this year, representing 7.6% of the market. By 2021, one in 10 US digital ad dollars will go to Amazon.

TikTok, the Chinese short-video app, is taking off in the US, India and elsewhere. It offers many unique marketing opportunities, such as the Hashtag Challenge, but marketers should take note of some risks.

Nine in 10 internet users in the US rely on email, and many say it’s a preferred channel for receiving brand communications. Email also still plays a central role for marketers looking to maintain and nurture relationships.

Biometric technology may soon give marketers the opportunity to learn more about their customers and deliver personalized messaging. While this could be a potential boon for business, it also has major privacy implications.