The Audi A3 began life exclusively as a hatchback car. It was only later in its life that it came out in Sedan and even Cabriolet guises. The Sedan has become very popular with drivers who want a four-door car and comfortable rear seating, but still do not want the larger size of the Audi A4.
The Audi A3 Sportback retains the sporty origins of the car in a four-door hatchback guise. The Sportback combines traits of the sedan, fastback coupe, and hatchback. The Audi A3 Sportback has the spacious interior dimensions of the sedan, combined with the sloping roofline and truncated rear end of a fastback coupe, and - of course - the rear door (boot) of a hatchback.
As you can imagine, this highly practical body design is a favorite among Audi drivers.