To carpet bomb auction house is to post a wide spread of items. This is commonly used with glyphs and jems. The way it works is to take just a few of every glyph or every gem you can cut and post all of them on the AH.
I carpet bomb glyphs. I take 2 of every glyph I can make and post them all on the AH. I under cut every glyph by a set amount. Someone like me that carpet bombs are playing the numbers. We expect so may people to buy our item but with so many categories and options, you never know what ones will sell that day. So by posting a glyph of each type, I know I will get the next sell no mater what glyph is purchased. I will keep getting sells until someone undercuts me.
In a market where you are the only one carpet bombing, you will have huge rewards with a small time investment. If everyone else does the same thing, you will have to post more often. I carpet bomb around 5 times a day at key times.
Sometimes I will have 1200+ glyphs on the AH from carpet bombing it. The people that are the best at this use Auctioneer's batch posting or Quick Auction 2 to do it. I bet other mods can do it, these two are the ones I have used. I prefer QA for glyphs.