Ask HN: how should early stage two sided marketplace get its user?

Something similar to airbnb, ebay, where it needs two users, seller and buyer, to work the marketplace.

how should an early startup gain its users? I assume some users would be reluctant unless seeing posts / listings.

do you think it is ethical to post fake/superficial listings just to generate buzz? some early beta users would not want to post listing unless seeing a little start.

just curious about everyone opinion. thanks.