General design for server software
For the server side code that generates status messages, we used a simple set of PHP scripts. The arduino periodically requests a message from the server to display. We have two types of scripts in our design. "Data gathering" scripts, and a single "Data consolidator" script.
The data gatheringscripts have one task. Whenever they are run, they grab the latest data for something you want to track. For example, say you care about the price of Bitcoin. The data gathering script for Bitcoin price gets the latest price and saves it in a file. Every time it gets the latest price of Bitcoin, it overwrites the contents of the file. The scripts can be run at an interval that you choose.
The data consolidator is run whenever the ticker wants the latest message. It simply looks at all the latest data written by the gathering scripts, consolidates it into one message and echo's it back. This is the message that the Arduino periodically grabs and displays.
The last piece of the puzzle is making sure the data gathering scripts are run as often as you want the data to be updated. (It makes sense to update subway data every minute, but not weather, for example). This is ideally handled by setting up cronjobs on your server, but for a quick and user friendly option we used a service called UptimeRobot. With it, you can configure urls that UptimeRobot will ping at intervals you specify. UptimeRobot automatically made requests from then on, ensuring that the data was updated. The image above shows an screen shot from our UptimeRobot dashboard.