Memomskid would have been cool too.
I have a fretless electric bass. I have not heard of a fretless guitar. It's all muscle memory and very, very carefully listening to yourself play. The nice thing about it is that if your string goes out of tune while you're playing, all you have to do to correct it is to adjust where your finger is a slight bit. That's one of the reasons I rarely ever play open notes on the bass. The other reason is that it made transposing a whole lot simpler. The not nice thing is that it requires precision of where you put your finger down. You can not put it down anywhere kind of close to the fret and get the right note. However, because no one is that tremendously precise, fretless basses have a distinctive groovy sound when played at or above the seventh fret. The further up the neck, the groovier it is because the little bit less precise the tone is (because there's smaller spaces between notes - any deviation has a larger effect). To enhance the 'fretless sound', I put flatwound strings on mine. Sooooo smooooooth. It's like playing strings made out of butter.
All electric basses used to be fretless just like double basses used in orchestras. It was Fender that first put frets on an electric bass to add precision to the tone that was played. Thus the name "Fender Precision Bass."