Attention Retailers: Amazon Prime Members Are Located in Aisle 5

The growing popularity of Amazon.com's membership program, Amazon Prime, has sent shockwaves among rival retailers since debuting a few years ago. For $79 a year, Prime members receive unlimited two-day free shipping on eligible Amazon purchases (with no minimum order size), as well as access to Amazon's video-on-demand service, Amazon Instant. The rate of adoption of Amazon Prime, coupled with the growing reach of Amazon, has caused rivals to scramble to offer alternative programs and initiatives to stay competitive, fearing that Prime dramatically lowers members' shopping activity on non-Amazon websites.