From Social Patterns
A content consumer needs to understand the source of a contribution and the source of a contribution needs to receive proper credit for his post. A user needs to assign her public identity when contributing content or joining an online community.
Use when contributing content, joining a community, or editing a public profile.
For the content consumer:
List the author's Display Name and Display Image (if space and performance permits) in close proximity to the title (or summary) of the post.
Link the Display Name and Display image to the most contextually relevant user profile. If a contextual profile is not available, link the Name and Image to the user's Primary Profile. Content Creator
For the content creator:
Reflect back the user's current public identity and give her the ability to update it prior to submitting content or joining a community. (see Reflectors pattern)
Based on the work of Matt Leacock, Sara Berg and Yahoo! Social Platform team