It might be "successful" (however you define that), but $8.3M in Revenue in 2014 (and an estimated $10M in 2015) on $50M in investment (not including Conde Naste's investment) in a 10 year period for a company valued at $500M and the 25th most visited site, seems like it's under-performing.
>>rhizom+g6
Underperforming versus it's competitors. I know of several websites that do 1/1000th of the traffic and have similar, if not better revenue.