Somewhere in 2011 I read an article about how much data Walmart collects hourly and how it is used to optimize their business. This incident ignited my interest in big data. I decided to explore more about how retail businesses and big data usage. Here are few interesting finds,
Wal-Mart, a retail giant, handles more than 1m customer transactions every hour, feeding databases estimated at more than 2.5 petabytes—the equivalent of 167 times the books in America's Library of Congress.  The magnitude of data is so big that, they recently shifted to 250-node Hadoop cluster. Walmart labs is building their own big data analysis tool and plan to open source them. 
Walmart was able to use Big Data analysis to drive a 10%-15% increase in completed online sales for $1 billion in incremental revenue, which is a well-planned ROI using data. Walmart recently acquired a big data start up dealing with real-time predictive analytics called Inkiru to make walmart labs more powerful.
Target is also one of the major players in retail industry. This interesting video claims Target not only know your name, age, address, (expected) salary but web browsing history. Companies collect lot of data in order to understand customers. More to add, prediction of retail companies is so advanced that it detected a girl being pregnant before her parents.