I imagine signposts as a single square sign that, upon construction, you get to write text on.
A signpost can be thought of as a lightweight story log - for example, you could place a signpost in the middle of a field where you fought an epic battle. The signpost can then read "Here we took a stand and kept a forty-man strong raiding party at bay. Ten brave colonists gave their life in defense of our great city." You can also use them as gravestones, writing a short epitaph for the colonist buried in the grave.
On the technical side of things, one possible implementation is to have the text being written upon completed construction of the signpost, in a prompt just like the city naming prompt.
The message can then be viewed with tool tip text when hovering over it.
A signpost can be thought of as a lightweight story log - for example, you could place a signpost in the middle of a field where you fought an epic battle. The signpost can then read "Here we took a stand and kept a forty-man strong raiding party at bay. Ten brave colonists gave their life in defense of our great city." You can also use them as gravestones, writing a short epitaph for the colonist buried in the grave.
On the technical side of things, one possible implementation is to have the text being written upon completed construction of the signpost, in a prompt just like the city naming prompt.
The message can then be viewed with tool tip text when hovering over it.