Last year was a pivotal one for Tumblr. The blogging network, which now has 170 million monthly visitors, for the first time began running ads last year.
CEO David Karp, who had famously stated the company was "pretty opposed to advertising. It really turns our stomachs," has reconsidered his stance. However, Karp maintains that for advertising to work on Tumblr, it has to have some creative merit.