- Shared Data. When someone design a product in a 3D CAD tool, the person manufacturing it can use that model to create their tooling. It makes having the same CAD software beneficial.
- Communication Devices. Work better when your friends are on them.
- Physical Places. Coffee Shops. Restaurants. Eventually you bring other people to the ones you like.
- Being Remarkable. People like to share things that are hard to believe. Something new.
- Discounts for groups.
- Credits for referrals.
- A good story. Everyone loves to share a good story.