Britney Spears’ new album, Femme Fatale, landed at #1 on the Billboard charts last week with a little help from social media. Her label, Jive Records, worked with Crowd Factory’s Social Offer so that visitors to Britney.com saw an offer to pre-order the album and share the offer with their friends. Then, if the visitors got 10 or more of their friends to visit Britney.com, they got a 20% off promo code for the entire Britney catalog. 30% of traffic to Britney.com came through Crowd Factory. Each sharer got six or more friends, on average, to visit the site.