Big box retailers’ web sites drove more than a billion search visits from July 2008 to July 2009, collectively spending about $678,000 per day on more than 1.2 million paid keywords, according to “The Big Box Retail Industry,” a new report from search engine optimization technology vendor Conductor that analyzed the search traffic of the top 10 big box retailers in the third quarter. Yet, despite the heavy investment in paid search, 66% of their traffic overall came from natural, or non-paid clicks.