As a result, free-shipping wars have emerged, with four out of five retailers saying they will offer such promotions at some point this holiday season, according to a Shop.org survey. Of course, Wal-Mart ( WMT)is looking to top rivals with its free shipping promotion on over 60,000 items, but Amazon ( AMZN) and Best Buy ( BBY)are keeping pace. Social networking has also become a bigger part of the equation, with companies like Gap ( GPS) and Macy's ( M) attempting to woo customers via Facebook. Overall, e-commerce sales are expected to grow 10% during the holiday season to $32 billion, according to Susquehanna Financial. But who will grab the most of these dollars remains to be seen. --Written by Jeanine Poggi in New York. >To contact the writer of this article, click here: Jeanine Poggi. >To follow the writer on Twitter, go to http://twitter.com/jpoggi. >To submit a news tip, send an email to: firstname.lastname@example.org.