The Hornet hasn't been around for as long as a lot of Honda's other bikes, but in the few short years since it's introduction it has become a very popular motorcycle.
Honda originally released the Hornet in Japan in 1996. This version used a 250cc engine based on the older 1986 CBR250Four, and the wheels from the 1992 CBR900RR Fireblade. Combined with the aggressive body styling (high level exhaust, fat rear tyre, etc) it quickly became very popular in the Japanese market. Unfortunately Honda never made it available (officially) outside Japan, but it can now be found in the UK as a grey import.
The popularity of the 250 Hornet lead to the development of the CB600F which was officially introduced to the UK in
1998, and it rapidly became as popular here as the 250 version was in Japan.
The CB600F model Hornet is a naked (no fairing) 599cc machine which uses a version of the CBR600 sports bike engine combined with a mono-backbone frame that uses the engine as a stressed component. This means that the engine is not mounted in a rigid frame (like on most other motorcycles) but is actually suspended below the frame with the engine casing providing a lot of the structural strength to the bike.
The engine itself has been re-tuned to produce less high-rev power but more low-rev torque than the sports bike it has been borrowed from. Obviously this makes the Hornet slower than the CBR, but this is no great loss when there is no fairing to protect the rider from the wind blast. The increased torque also makes the Hornet more drivable around town, which more than makes up for the loss of top-end power.