While looking for some gardening supplies online today, I discovered
several different retailers, all claiming to be different businesses
with different locations and contact info. However, every single one
of them had the exact same site structure, the same scripting, and the
items offered at each site are exactly the same. If one site is out of
something, every other site is also out.

What is going on? Is this some sort of scam?

Here is a list of all of the sites I have found like this so far:

http://www.awbrown.com
http://www.bayportflower.com
http://www.berkshirenursery.com
http://www.chnursery.com
http://www.countrygardensinc.com
http://www.cousinsgardencenter.com
http://www.daysgarden.com
http://www.forthillnursery.com
http://www.gardenist.com
http://www.gloriasgardencenter.com
http://www.great-gardeners.com
http://www.harborgardens.com
http://www.hitherbrook.com
http://www.homegardendirect.com
http://www.hoosierlandscapes.com
http://www.igardenworld.com
http://www.laddsgardencenter.com
http://www.maxwellturf.com
http://www.mcardles.com
http://www.mcnaughtonsgardens.com
http://www.riverside-nursery.com
http://www.russellsgardencenter.com
http://www.shannonflorist.com
http://www.thegardenspot.com
http://www.tomsgarden.com
http://www.tripleoaks.com
http://www.twomblynursery.com
http://www.zergott.com