Looked at from another angle, however, Tumblr is among the most important sites online — a central hub of what is nebulously known as “internet culture.” … Tumblr’s most famous legacy is probably the reaction GIF, which was popularized by Tumblr accounts like What Should We Call Me. Tumblr’s reblog structure, which created lengthy, publicly shared conversations between strangers, also helped popularize the concept of the Discourse, the internetwide conversation happening all at once. It is also the primary meeting place for fandoms of shows like Doctor Who and Supernatural, and films like the Marvel movies — some of the most aggressive fandoms are cultivated on Tumblr.

Tumblr’s Unclear Future Shows That There’s No Money in Internet Culture | select/all