This is a point Reid Hoffman makes in Blitzscaling: network effects are nice when a company grows, but they’re terrible when it’s subscale.
Marketplaces are so hard to get rolling that you should expect to take heroic measures at first. In Airbnb’s case, these consisted of going door to door in New York, recruiting new users and helping existing ones improve their listings.
mostly you have to choose the scale of your desired S-curve, where newtork effects can bu built, the egg and chicken death loop risolved with some affordable marketing effort
Groupon -> sign up merchants in a city and get user to signup with percks, cinema tickets in citydeal
These are basic concepts but nicely explained here Surfing the Right S-Curve