Take advantage of existing social Connections within Yahoo!
instead of establishing your own graph from scratch.
Show user activities that encourage interaction with your
application.
Make your application spread virally by letting people share it in different ways at
Yahoo!.
Use Yahoo! as your megaphone to showcase user activity.
Do's
Surface a user's friends inside your application to encourage
competition and interaction. (Example: Hey
Einstein)
Write informative, inviting messages that encourage other
users to click. (Example: "Mark has rated the book Adventures of
Huckleberry Finn: 4/5 stars" via Books weRead)
Advertise user activity through Yahoo!
Updates (activity stream).
Don'ts
Don't ask users to create an entirely new set of relationships
inside your application.