Consumers, including celebrities such as Reese Witherspoon and Jessica Alba, recently responded to an e.l.f. Cosmetics' TikTok hashtag challenge by creating 2 million videos, and Chief Marketing Officer Kory Marchisotto credits much of the success to the inclusion of its original 15-second song, "Eyes.Lips.Face," by popular songwriter iLL Wayno and Holla FyeSixWun and follow-up track that's climbing the Spotify charts. Evan Horowitz of e.l.f.'s agency Movers+Shakers says, "TikTok is such a unique opportunity especially in this moment and time" because the platform is mature, has a large, engaged community and little brand competition.

GLOW's Jennifer Fink and Sarah Pine share a six-step guide to making social users feel as though they're part of live events, beginning by establishing goals for the event that can then be translated into a social strategy and mapping out team roles for each platform in advance. Create an on-site war room to coordinate communication, adapt strategies in real time based on social feedback and use content from the event to keep the social conversation going, they recommend.

Bannersnack displays 10 key digital design trends and tips for next year in this infographic, including the use of bold typography and custom-branded illustrations as exemplified by LinkedIn, Slack and Airbnb. Other trends highlighted are the use of short-form video incorporating interactivity and color gradients.

Skin care company Bliss uses coordinated consumer quizzes and polls in social posts, ads and other online sites to garner personal consumer recommendations and valuable data for product development. "Brands [are no longer focused] on big data anymore, instead focusing on four or five important points of actionable data," and a quiz lets brands "set the attributes they want to capture," says Pam Erlichman, chief marketing officer of quiz-creation company Jebbit.

Snap, Gucci and filmmaker Harmony Korine partnered to create 50 limited-edition Spectacles 3 sunglasses, made exclusively for creators at Art Basel Miami Beach 2019, which Snapchat users can try on virtually. Korine created a "Duck Duck" video filmed entirely using the sunglasses, creating an immersive story that combines augmented reality with 3D effects, and the filmmaker says, "Spectacles 3 is a completely unique format that shifted my perspective on film, narrative, what's animated and what's real."

Unilever's "Homemade Unfiltered" video series features food author and restaurateur Ayesha Curry creating dishes using Hellman's and Best Foods mayonnaise. Partnering with Believe Brand Studio at Believe Entertainment Group, the six-video series will appear on social media and promote the products and audience participation beforehand by releasing recipes and shopping lists.

Twitter has launched @TwitterRetweets, an account that highlights popular tweets that went viral and drew significant user engagement. The social platform also relaunched its Instagram account, where it plans to include screenshots of Tweets that are resonating with consumers.

YouTube has released its "Rewind 2019: For the Record" video, which showcases viral videos and creators from the past year, and it has so far attracted more than 23 million views. Adweek's David Cohen also lists the platform's most popular content of the year, including the top 10 trending videos, the most-viewed videos from creators, the "top breakout creators" and more.