Imagine Facebook doesn't have any marketplace product and you have been tasked to build it. What is your mission, goal and success metrics?

Imagine that an engineer is suggesting you an idea to build a feature similar to people you may know to showcase items on the news feed. How would you prioritize this?

Let me assume that we don't have any product related to the marketplace before.

Initially, I would like to think about the vision for this feature and try to tie it with FB's vision. Later, I would go think upon a goal that is of higher priority and think of the actions of a user that helps in attaining the Goal mentioned earlier. Finally, I'll list out metrics and prioritize the most important ones. 

Vision:

The Vision of FB is to give power to the people so that they could build a meaningful community and to help them bring the World closer.  With this in mind, I guess the vision of the Marketplace should be helping the Buyers and Sellers form a meaningful community and help them to reduce the distance between them.

Goal:

Since the Product is something new, the goal will be to acquire more and more users and to increase engagement rather than focussing on revenue.

Placement:

I would like to build it in the FB ecosystem itself and would also make sure that this feature's presence doesn't disturb the user journey of a non-buyer and non-seller. This is because of the priority that needs to be given to a user's comfortability and our responsibility to make sure a user doesn't find the placement disturbing.

With this in mind, I would not go with the Engineer's Suggestion of having this feature shown like "People You May Know". Though this helps in making the users aware of the feature easily, We should not forget that not all the users of FB are going to be a buyer/ seller, and to respect their choice it's best to place it somewhere separately.

User Journey:

• Awareness n Discoverability of this feature
• A need emerges to sell/buy
• Opens this and gives a listing/ searches for a product.
• Gets their ad placed/ find the required product.

1. Discoverability of the feature
2. Engagement

1. Discoverability/ User-Friendliness
   1. # of clicks to open MarketPlace Tab/ #of the total number of users
   2. # of listings created/ # of clicks on "Create New Listing".
2. Engagement
   1. # of searches performed or ads posted / 1000 sessions
   2. # of searches per user per 1000 session
   3. # of interactions like saving, sharing, or messaging