You might get as many different answers the number of people you ask.
Traditionally speaking, the true seven fold tie was constructed from one large piece of silk, which was unlined, and accordion folded in on itself 7 times. The tips were then hand-rolled up, and hand stitched. It was thought that the added heft and vertical folds of the silk would prevent twisting, and the weight would add to the substance of the knot.
While we have a handful of these unlined "true" seven-fold ties available in our inventory to satisfy our "purists", most of our customers prefer an updated version of this classic that is lined, and backed. It it technically a double four-fold tie. Although, for the sake of consistency throughout the international necktie market, we decided, like Kiton, Brioni, Bulgari and others, to continue to refer to it generically as a 7-fold tie.