Wal-Mart Stores Inc. has bought Social Calendar, a Facebook application that reminds consumers of their friends’ birthdays and upcoming holidays and enables them to post virtual photo cards and other greetings on friends’ Facebook walls or Timelines.

The Timeline replaces a consumer’s wall and profile with a virtual scrapbook that features a graphical and chronological timeline of events of her life on the social network, and other interests that she chooses to share, such as the bands whose concerts she has attended and the clothes she has bought.

It’s unclear what Wal-Mart’s intentions are with Social Calendar, but the world’s largest retailer won’t shutter the application. “Wal-Mart will be integrating it into our ongoing efforts,” a spokeswoman for the retail chain says.  “The founder, Raj Lalwani, will stay on as an advisor to the @WalmartLabs team for the short term.”

The move is the latest effort by Wal-Mart to leverage social media. The retail chain last year bought Kosmix, a Silicon Valley company that specialized in mining data from social networks in order to make targeted offers to consumers. The Kosmix staff of about 70 then became the core of a new mobile and social development center that Wal-Mart calls @WalMartLabs, which develops technology that ties together social and mobile channels with in-store shopping.

Among the offerings the lab has rolled out is Shopycat, a Facebook application that, with the permission of a Facebook user, culls the posts and Likes of that consumer’s friends on the social network to present gift recommendations from Walmart.com, as well as from about 20 other online retail sites, including BarnesandNoble.com.

Wal-Mart, No. 6 in the Internet Retailer Top 500 Guide, completed the Social Calendar acquisition on Friday.

Joel Anderson, the president and CEO of Walmart.com, U.S. will speak at theInternet Retailer Conference and Exhibition 2012.  He will speak in a session entitled “Creating innovation through the next generation of retail” on June 6 from 9:15 a.m. to 9:45 a.m.