They've apparently been quietly doing it since January of 2012, but I want to applaud RTA for officially making their GTFS (Google Transit Feed Specification) data available to the public, via the GTFS Data Exchange. Open data is really awesome. For those of you who know why open data is awesome, you can stop reading. For the rest of you, a basic primer.
So in this context, a GTFS feed contains the stop, route, and schedule data needed for a transit agency to get on Google Transit. Because Google is the all-powerful data-sucking beast that it is, and because they're really the first people to try to integrate multiple transit agencies' data on a massive scale, it's become a de facto standard for electronically publishing transit information. RTA has obviously had a GTFS feed for a while, since they've been on Google Transit since 2009. To my knowledge, however, while the feed URL was easily discovered with a little creative Googling, the data was not officially publicly available. That meant that the only people who could incorporate it were Google-- and that the vast ecosystem of transit app developers using public GTFS data couldn't incorporate RTA's information as well. This includes not only transit apps like HopStop, but also things like WalkScore, which incorporates transit information and travel times, and AutNo, which allows you to search for apartments within transit commute distance of your work.
Now, with publicly-available data, those tools can integrate RTA's transit schedules in order to give people a better idea as to what their transportation options are-- especially when looking for new housing choices.
What I'd love to see next is the integration of real-time arrival data (which, unbeknownst to many, RTA does have) into the GTFS feed, so instead of a trip plan based on schedules, Google Maps could give you a routing based on which buses were on time, which were late, etc. You might find that a connection that you should, on paper, just miss is actually running a few minutes behind, saving you a long wait, or that, because your bus is late, taking another route might get you there faster. Transit aficionados like myself already know that sort of information, but it'd be cool to make it available to anyone via their smartphones.
Still, though, kudos on the open data, RTA.