Tumblr is lagging well behind its competitors and the industry as a whole when it comes to growing its user base. In our latest forecast on social network usage, eMarketer predicts the social network will fall farther behind its competitors over the next four years.

Tumblr is a young company, starting from a small user base. As such, its reach among internet users is 8.7%, far below the 69.9% who use social networks in general. Tumblr is most heavily used by Americans ages 25 to 34, who are also the heaviest users of social networks in general.
Regarding its total user base, this will be the last year Tumblr will grow by double digits, signaling a plateau. In 2016, Tumblr will have 23.2 million users in the US. That’s less than half as many as Pinterest (which has 54.6 million) and less than a third as many as Instagram (which has 89.4 million).
Perhaps even more telling regarding usage, the gap between Tumblr and its competitors will widen through 2020. Over the next four years, Instagram will add 26.9 million users, Facebook will add 14.6 million and Pinterest will add 12 million, but Tumblr will add just 6.2 million users.

“A big factor is that Facebook, Instagram and Twitter are more successful at catering to mobile audiences,” said eMarketer forecasting analyst Oscar Orozco. “Tumblr is pushing for new ways of sharing content on its platform, including video, messaging and GIFs – hoping to increase mobile engagement.”
Yahoo, which purchased Tumblr in 2013, has hoped the social destination would boost its shrinking share of the US ad market. This year, Yahoo will capture 1.3% of total US digital ad spending, a slight decrease over last year. And its share of US display spending will drop to 4.0% this year, from 4.8% in 2015.