Alibris Inc., which operates Alibris.com, an online marketplace for 12,000 sellers of new and used books, CDs, and DVDs, credits more business partners and bargain-hunting shoppers with increasing online sales year over year by 10% in 2009.

Sales increased by growing and expanding our business partners, as well as from people looking for good deals on new and used books and other products in the recession, Alibris president and CEO Brian Elliott tells Internet Retailer.

This week, Alibris announced it had joined mass merchandise retailer Buy.com’s online marketplace, offering Buy.com customers access to 2.9 million new, hard-to-find, collectible, and used books in the Alibris catalog. To integrate with Buy.com, Alibris used Buy.com’s seller technology and its own internally developed information technology-called Partner Integration Framework-which enables Alibris to integrate with other companies’ information systems in as little as four weeks, Alibris says. Buy.com is No. 33.

Our independent booksellers asked us to help them sell more books, Elliott says. Our partnership with Buy.com achieves that goal by providing our sellers with access to the millions of eager shoppers who already flock to Buy.com in search of a wide variety of products at competitive prices.

Other recently added business partners include Waterstone’s, a United Kingdom books retailer, in November, and Better World Books, a for-profit venture that collects and sells new and used books online and donates a percentage of each sale to help fund literacy initiatives worldwide. The arrangement with Better World, which launched six months ago, has generated more than $1.5 million in book sales for Alibris’ independent sellers of new and used books, Better World says.

Jeff Wisot, vice president of marketing at Buy.com, is speaking at the Internet Retailer Conference & Exhibition, June 8-11 in Chicago, in a session titled The issues that e-marketers struggle with.