Need more users for my internet startup (Growthhacking) (Marketplace)

To overcome the "chicken and egg"-challenge when growing a marketplace, focus on getting the "producers" (sellers/merchants etc.) on board first.

One technique is to do that is by providing a service which allows producers to cater to their existing consumers in a better way. This way they will naturally bring consumers, and once the consumers are on the platform they will see offers from other providers (than the one which brought them to the platform) and make it work like a real marketplace. 

See examples for this on Platformed.

If your platform allows producers to showcase their work then they will bring clients naturally to the platform.

Youtube is a classic example: after users uploaded their videos they want the videos to get watched often. So they spread the links to it and therefore - even if they didn't intend that - help Youtube to grow. 

A good example for this is Yelp: 

Yelp provided information about certain restaurants (without the restaurants' involvement) which users (consumers) could vote and comment on. After the restaurants got a lot of reviews there was a strong incentive for the restaurants to "claim" their space on Yelp (so that they can modify their description, upload pictures etc.) and therefore they got onboarded later, i.e. at the end there were both parties needed for a marketplace. 

Check out Platformed to learn how this might be generalized for other marketplaces as well.  

When you start out you may not have your producers (creators/sellers etc.) on board. However, if you're an information platform you may use existing producers' information from other platforms and present it in a better way, e.g. with a better description, pictures, a better search function and/or navigation experience.

For example, several startups have used Craigslist as a source of information and presented it in a better way (which however Craigslist is not always too fond of). 

Another example is this solution (for growing Solutionbay), based on the content on Platformed.

Think how you can provide value to one user group (producer's or consumers) which doesn't require the other user group, i.e. which doesn't require a marketplace (yet). 

Examples for this are Square, OpenTable, Delicious and Instagram as described here and here.

This means: Maybe you have to start out as something entirely different than what you have in mind long-term, just so that you reach critical mass which is required for a marketplace to work.

In most marketplaces one user group is more difficult to acquire than the other - the classic example are dating sites, where it's much easier to get men to join than women. 

So how to get the "difficult" user group to join? One option are monetary incentives (e.g. free drinks for girls) but also non-monetary incentives may work as described here. 

To get things started, consider creating the first products/content yourself to kickstart the marketplace with some initial supply. 

Two examples:

• When Apple launched the app store, they created a range of apps themselves so that people could download at least something. Later third party developed apps took over as we all know. 
• I (co-founder of Solutionbay) entered this solution ;)

Building two-sided marketplaces is difficult enough. Three-sided marketplaces are almost impossible to create - unless you know some tricks. 

In the video below, Bastian Lehmann from Postmates talks about how they successfully built a three-sided marketplace. Postmates is a delivery service with three sides: 1.) Merchants (who sell the products), 2.) Delivery guys (who deliver the products to consumers) and 3.) Consumers. 

In a nutshell, Bastian proposes to focus on two sides first (three at once is too difficult) and then later approach the third. He suggests to leave the side to target last which does not require interaction with both parties (i.e. in his case the merchants).

Watch the video to get the full story: