The issue with that approach is largely a performance one, judging from what I know of flightcaster. If they have to issue a search to twitter for the flight i

The issue with that approach is largely a performance one, judging from what I know of flightcaster. If they have to issue a search to twitter for the flight info, the user has to wait on it. If they constantly poll, then there are thousands of flights and they have to poll them regularly to make sure they have the latest info on the flight. IIRC, the current algorithms include historical ontime percentages and weather, but I don't remember reading about them using the realtime web or airline's websites to gather it. Of course I don't really know what I'm talking about, it's all conjecture.