[MyTurn2Raise]

funny thing...I've been incarcerated over this very drug.
The date rape angle is a sick twist of a minority of users. The vast majority use it as the 'healthy' alternative to alcohol. It bonds in the brain in the same synapses that GABA does, causing similar effects. It also causes a blockage of dopamine receptors. When the drug wears off, the dopamine floods the system again, creating a second high.

You get a good nights sleep, with rem, after taking it. Neglible hangover effects
It's a precursor to release of the Human Growth Hormone; good for muscle growth, restfulness, and such. It was originally a big thing among bodybuilders for that very reason.

Hmm....It's technically a salt. However, it's quite potent in small doses and would be tough to measure out as such. Thus, it is commonly mixed in water and dilutes completely (water stays colorless and odorless). The taste is quite salty, like saline solution. Back in the day (99), It was diluted so that a shot of the salty water was a very reasonable dose for a 165 lb body.
(Obviously, many naredowells figured out this was pretty easy to mix into drinks unknowingly--there are always bad apples that ruin it for everyone else.)
You could commonly buy it in 16oz waterbottles or gallon jugs for the ambitious. Street cost would be $5/dose back in 99 when buying one time deals. However, that is quite a mark-up from the costs of production. Those that buy in large quantities can get it easily for half that price. It's quite easy to produce.

Accurate tests--not really when it's consumed...it goes through the body quite quickly and the body naturally produces quite a bit of this stuffand masks it, enough to make it difficult to find out a person took it as little as 4 hours later.

Post-mortem--Do not know

They can definitely test liquids consumed from glasses/bottles/cans/etc and tell if GHB is in it.

The whole 'date rape' label is quite a misnomer. 99+% of use does not relate to that angle at all. There have been very few cases where a GHB date rape spiking has been proven. However, the connotation is quite bad. States Attorneys have become real pricks about the drug no matter it's intended use.

Let's say the 3 year sentence for mere possession was an eye opener.