Building a social network

It’s too complex with social networks. Even Google failed with its Google+ since there’s Facebook already.
 
So, when we’re talking about a social network – it needs to be unique to some extent: provide unique features, have different use cases or target the specific audience or niche. For example, Instagram was successful, even though there was Facebook already. All because it had a focus on photos. Same for Pinterest. It provides different features and a different focus.
 
Also, social networks can develop around the products like MMO games, or specific life spheres like a business, investments (LinkedIn, AngelList).
 
The main thing is to provide users some unique value.
All the rest is marketing: promote your social network, implement seamless and easy registration, i.e. via Facebook. Make the start of using it as simple as possible.
And if we’re talking about the marketplace – there’s some difference, since marketplace sells paid content. However, the main thing remains the same: you need to create a unique value. For example, the Steam marketplace for PC games has been live for over 16 years already. And Epic Games Store has been just recently released at the end of 2018, and it became successful.
 
What did they do?
1. They published some great exclusive titles on their stores. (The unique value for customers. And of course, it costs money which is being paid to developers and it’s an investment).
2. They’ve made a commission from selling games much smaller than on Steam, so game developers who publish their games on Epic Games Store can get more revenue. (That’s the unique value for game developers who are sellers in our case. It also costs money and is an investment).
So, the common strategy is to create a unique value for all the participants of the marketplace. And to create it you often need to invest your costs and be non-profitable for some period of time, in order to get awareness.