White whiskey (or white dog, white lightning, moonshine) is simply unaged whiskey.  The thing that makes whiskey good is the aging in wooden barrels.  So white whiskey takes all the good parts of whiskey and removes them so you're left with only the bad stuff.  Put another way
White whiskey, then, is simply corn liquor that either never made it in the barrel or spent so little time in it to not matter. Consequently, it's clear as water, but hot with alcohol, harsh to drink and tastes heavily (and miserably) of sweet corn. All in all, it's not a very good spirit.
Slate says it even better:  "It tastes horrible."  It's true, the stuff is disgusting.  It's sort of like vodka, except more flavorful, and hence worse.  It's amazing that this has become a trend.  I was at a whiskey tasting and overheard a guy ask the bartender how to drink it (i.e. what to look for in smell, taste), and the bartender simply said "quickly".  Of all the myriad configurations of ethanol you can pour down your gullet, why anyone would choose something that's actively disgusting is beyond me.  If you want crappy whiskey, go with one of those giant plastic gallon jugs at the liquor store.  If you want to be extra American, pick anything with the word "bourbon" in it.  If you want something cheap, how about Jim Beam?  My point is that nobody is gaining anything by drinking white whiskey, except the distillers who are selling an unfinished product for much more than it's worth. #products