Design-oriented retailer Fab.com has seen its referral traffic from Facebook double since upgrading for timeline, and its membership has shot up to 3.2 million from 1.8 million.

In a post on the Facebook developers blog, Fab.com was touted for using action verbs including bought and faved, and for aggregating content including purchases, favorites, and I just bought this. The blog post went on to say:

Fab.com offers a limited-time, promotional monthly credit to encourage people to opt into the social shopping experience. Fab.com also displays a face pile of friends during authentication to make the experience more relevant to each person, which increases conversion.

Fab.com prompts people to use the most popular feature — add to favorites — on their product pages to increase sharing and generate stories that appear in news feed and timeline on Facebook.