1. Static wooden signs - These are simply to mark something, you could put one in front of a train station to label it, or you could label storage in chests etc. Pretty basic and boring, but does have it's uses.
2. Electric signs/billboards. Yep, think what the guys working on your local roads use - those big flashing signs. These could open up a huge amount of oportunities for the player - especially if they could be controlled and influenced by the circuit system. I can see multiple instances where I would use them;
- To notify the player of a condition change such as a chest being empty (ie. a chest being used to fuel a train station)
- To notify the player that consumption of power > production of power
- Oil reservoirs have depleted down to 0.1/s
- To make a visual display of a particular number of items held in a logistics network
What do you guys think?