Digital signs are there to service a need for information. People will only look at a digital sign if there is some information being shown that they need, or are interested in. It's important then to ensure a good mix of information and targeted advertising (if desired) to meet the business's goals. For example, combine a list of upcoming events with a list of sports results, a news feed or bus times to draw attention. It can schedule different items to be shown at different times of the day. Be sure to target content to the times when your target audiences are in the building (eg advertise events for young children when parents are arriving to drop of or collect children for an existing event). People need to be able to read what is on the sign. Be sure to take a look at your completed work and make sure it's possible to read it in the time that it appears on the screen, and that the font size is large enough etc.
IP Technics provides multi-display, multi-zone, fully scheduled Open Source based digital signage solution controlled from a centrally managed web interface.