The doorbuster(s) traditionally started at 5 or 6AM on the Friday after Thanksgiving (a.k.a. Black Friday) causing the rabid and sleep deprived consumer to wait, nose pressed to the door, to "bust the door down" at store opening time to get one of these "too good to be true" doorbuster deals and fall prey to classic Red Herring or bait and switch product selling/marketing ploys.
This trap lures the unwitting consumer in for one particular doorbuster "too good to be true" deal, engineered to be available only in extremely limited quantities, and then when these items are gone "for no apparent reason" AMAZINGLY the store is able to offer a similarly craptastic item but at a much better price point for the store. This causes the severely sleep deprived consumer who doesn't wish to feel defeated by walking away from the store empty handed to purchase any substitute regardless if it was anywhere near the price/features of the original doorbuster much to the delight of the merchant.
The doorbuster(s) and the carefully crafted ways in which they exist are the brainchild of mutant, non-charismatic and frequently sexually frustrated marketing types which prey on defenseless consumers who dont know any better than to fall into a classic trap that retailers want them to by purchhasing items they don't really need or want, nor does anyone they know need or want, but since its "such an awesome deal" feel they should wake up at 4AM to get at least one of anyway.
Jeff: Um none dipshit, its Thanksgiving, Friday is tomorrow.
Sarah: I got up at 4AM to be one of the first ones to stand in line at Best City to get a Sankyo HD DVD & VHS combo player for $12 but the nice manager said they were all out but showed me this Fony Blu-Ray & Beta tape combo player that I ended up getting for $1100 on my new 29% interest rate Best City card!
Dan: Sarah you are one f'ing sleep deprived moron LOL!
Dave: I got up at 3AM to be the first on Ebay to get the Friday doorbusters!
Dirk: WTF are you talking about??
Betty: Hey honey I got a great doorbuster deal on this Ronco broccoli dicer for $7!