Wal-Mart (WMT -0.27%) is expanding an online shopping program that allows in-store pickup at lockers. This comes after much success by Amazon.com (AMZN -1.41%) offering two-day shipping with its Prime service and shows some willingness by the retail industry to adjust to consumer behavior. Is this a one-off move or a trend other retailers will follow? The Fool's Erin Miller sat down with Travis Hoium to find out.