I'm interested in a lot of different forms of transportation as a hobby. Photography, tracking, etc. Being able to see the flight history of a specific airframe is interesting to me or going back and looking at past flights. Fleets is another feature I use. For example, I've been interested in trying to get photos of the new E915-E2 jets that Porter Airlines is adding so I've created a "fleet" and can easily track the whereabouts in the hopes of being able to catch one in flight to photograph.