Hello Luc, yes i have that AIS site on my fav list, though i am not primarily a ship spotter but one of aircraft.  The data on that AIS site is similarly transmitted by aircraft, and is refered to as S Mode.  I have a reciever and prog called SBS1 by Kinetics Aviation that allows a virtual radar on my pc. On spotting a particular aircraft approaching on screen, i can then go into the garden with the binos and see the real item.  Radio communication can accompany this, but due to laws in this country prohibiting this, i of course wouldn't dream of listening *smile*.  Bit off subject, but i thought it may interest you.  (Type, heading, speed, height and call sign all displayed.  And owner, when i update from 'gatwick Aviation' data base).