• by Gavin O'Malley  @mp_gavin, April 16, 2015

With Nike in tow, Tumblr is rolling out what appears to be its fanciest ad unit yet.

Video-based and full screen-sized, the “Sponsored Day” units give brands the power to take over users’ dashboards for a full 24 hours -- from midnight to midnight. Appealing to a broader brand base, the “Sponsored Day” unit is the first to welcome marketers without an existing Tumblr blog.

The new units are "the biggest and boldest opportunity for marketers to engage with our ... community," David Hayes, Head of Creative Strategy at Tumblr, said on Thursday.

Underneath the big video header, brands can feature their own content or curate posts from the Tumblr community via the Explore Tab. “The Explore Tab is the destination for Internet culture and your guide to the best stuff on the Internet today [including] personal recommendations, trending topics, staff picks and more,” a Tumblr spokeswoman said.

Since dropping about $1 billion on Tumblr in 2013, Yahoo has made a number of efforts to expand the social network’s appeal among mainstream audiences, creatives and marketers.

Tumblr recently launched a Creatrs Network to connect artists with brands. During a test phase, the initiative resulted in successful collaborations between artists and brands like Axe, Gap and Olay.

Tumblr also recently announced support for long-form content and mobile messaging. While pictures and video are driving social media trends at the moment, there is still demand for blog-like platforms that spotlight the written word.

Last year, Yahoo announced the launch of a new content marketing solution built specifically for the social network.

By its own count, Tumblr currently claims an audience of roughly 460 million unique visitors.

Yahoo recently said it expected Tumblr to take in more than $100 million in ad revenue -- and achieve positive EBITDA -- in 2015. Coming from CEO Marissa Mayer during Yahoo's quarterly earnings call, the disclosure offered a rare glimpse of Tumblr’s financial health.

Breaking down Tumblr’s ad business, Mayer said 150 brands pay for a presence on the social platform. On Thursday, a Tumblr spokeswoman said that number has since increased to 300 brands.