Marketing is used to attract both new sellers and new buyers. It is important to compare marketing expenses growth with revenue growth, since if the revenue growth lags behind then marketing is innefective.
Last reported quarter 2018 Q3 it was $39.52 million, up by 68% year-over-year from $23.52 million. From $82.80 million in 2016 it increased by 32% to $109.09 million in 2017.
Source: Etsy Quarterly Results.