As social networking sites like Facebook and Twitter grow worldwide, more Internet retailers are beefing up their efforts to add social twists to their business, trying to define the idea of \"social commerce\" and capitalize the opportunity. On Wednesday, online auction giant eBay revealed some of the social features it is planning to launch later this year, while Copious, a San Francisco-based startup, launched its online social commerce marketplace with a slogan of \"buying from and selling to people, not strangers.\" Copious asks users to log in through their Facebook accounts and allows buyers and sellers to see if they have friends in common in their social networking sites. Buyers can see more information about a seller and also see whether anyone in their networks has purchased, shared or commented on an item from a specific seller, rather than anonymity or simple profiles on sites like eBay and Craigslist. As for sellers, Copious has a social pricing mechanism that enables a seller to offer buyers discounts for sharing listings on Facebook and for following the seller on Copious. Jonathan Ehrlich, Copious co-founder and former Facebook head of marketing, told technology blog TechCrunch that the site is centralized around using social data as a signal to help users understand and trust other parties. According to Copious, the startup founded in January 2011 has raised two million U.S. dollars in funding from Foundation Capital, Google Ventures, Blackberry Partners Fund and a number of Silicon Valley angel investors. Also on Wednesday, Christopher Payne, vice president and head of eBay North America, delivered a keynote speech at the Internet Retailer Conference and Exhibition 2011 in San Diego, revealing some features eBay is launching during the social trend. One feature will enable users to log in their Facebook account on eBay\'s homepage to get product recommendations based on one\'s purchasing history and things they have \"liked\" on their Facebook page. Another feature will allow users to post multiple products on their Facebook page to get their friends\' opinions and ask them to vote for the final purchase. EBay has been stepping up its social efforts, and Payne said on Wednesday that social is a top-level initiative for Internet retailers. Last month, eBay hired former Yahoo executive Don Bradford to lead its social commerce efforts. Last November, it launched Group Gifts service, enabling users to chip in to buy a gift for someone. A research by Adgregate Market in March showed that more brand websites are losing traffic to their Facebook pages. The study revealed that the \"Facebook stores\" of most Internet retailers are more efficient at acquiring visitors, indicating social commerce is poised to take off. Although the idea of social commerce is still new, more companies are trying to seize the opportunity in their own moves. There are many other companies taking the social commerce model. Oodle, the exclusive provider of classified ads on the Facebook Marketplace, rolled out a series of social features last December to make more money from social classifieds. In February, Payvment Inc. launched a Facebook Mall, where consumers can shop for more than 1.2 million products among 60,000 retailers in a single shopping cart. Yardsellr, which is often called \"an eBay for Facebook,\" allows sellers to list items at fixed prices in different categories called \"blocks,\" such as jewelry and purses. Prospective buyers can \"like\" the \"blocks\" they are interested in on the Yardsellr website or its Facebook page, and then they will get Facebook news feed if a seller has something to offer in the category. Yardsellr said 1.5 million people were following its \"blocks\" by late December 2010 and the number of new followers is growing by 20,000 daily.