Online platforms work on principles similar to offline communities. The onset of crime and vandalism in a community can lead to large-scale abandonment. The same applies to online communities and marketplaces, especially as they grow in size.
Network effects make a community more valuable as it scales. However, the onset of vandalism could make network effects work in reverse if the system doesn’t scale its ability to govern user activity. When this happens, fast-growing networks start losing users en-masse, online conversations enter the realm of the ridiculous (think YouTube) comments and online decisions may even end up leading to unpleasant consequences offline (think ransacked house of Airbnb host).
Startups that succeed at gaining traction and scale rapidly can still end up failing if they fail to create abuse control systems that prevent, regulate and cure the onset of such abusive activity.