I am a big fan of Megabus, the new bargain bus company that has totally completely and utterly changed everything about bus travel. They have great bargains for their fares (and yes, I am occasionally able to find the one buck fares that they advertise) and best of all you actually buy a seat on a specific bus. Unlike the Greyhound or the Chinatown buses, where you buy a ticket for some bus traveling between your destinations, hopefully the one you want to be on, but maybe not. This means that interstate bus travel is not only less stressful, but actually dependable. This makes a big difference for me, since I am mostly traveling for work.
One of the ways Megabus keeps their bus travel so (relatively) cheap is that they don't have a lot of extras. You know, like actual buildings to wait in or actual employees where you catch the bus. And because they don't have an actual place to pull into, they do things like pulling up on street corners, grabbing their passengers and their suitcases, and taking off.
This leads to the most annoying part of Megabus: because there aren't any employees to ask if the bus is coming or not, when the Megabus is late (which it is, not infrequently) you are left simmering in great anger, unable to figure out if the bus is on its way, been canceled or, just as likely, were forced to move their bus stop to a more suitable place.
So, unlike most apps developed by big companies, the Megabus app actually addresses their biggest problem. You can enter the megabus number and arrival time and see in real time where the bus is. It still doesn't tell you why the bus is late, but just knowing it is on its way (or isn't) is really useful.
It will be even more useful when they add their heavily traveled east coast routes.