I track a number of new apps and website technologies as part of my work. Came across this today direct-flights.com (not to be confused with a bunch of similarly named flight booking sites). It's claim to fame is that it shows all direct flights from any particular airport. After a quick play round, it does indeed seem to do that in a fairly clear and intuitive way. It would have saved me a fair bit of time during recent planning of some flights through Turkey and Greece (i.e. it found exactly what I ended up with but in about a tenth of the time). The interface is not perfect but as an ultrafast way of seeing where you might be able to hop to from any particular airport it seems to deliver.