Etsy is a $2B company. To gain initial users guys from Etsy created a team to attend craft shows across US and Canada. Their hack was in noticing a growing feminist-driven crafting movement, so they were attending craft-shows and convincing experienced feminist crafters to join Etsy and run their stores on Etsy platform.
It was a perfect moment, because there were no such platforms to easily start selling crafts online (except Ebay, probably). So all these crafters were extremely motivated to start their business on Etsy.