What are labor points? Labor points are numbers that represent an individual character's ability to directly affect the game world. Players can use their labour points to contribute to the building of infrastructure, to assist in production and for destructive purposes as well. Each character starts with a certain number. Additional points are gained slowly over real-time, whether a character is logged in or not. The total number of points that can be accumulated is capped at some arbitrary number.
My overall concept for this system includes several other layers such as skills, hired NPCs, varied building sizes, trade routes and other good stuff that would interact with the Labor Points System in a meaningful way. But, in order to keep things simple and focused, I'll be foregoing discussion of those at this time to keep this essay as basic as I can.
Lets start with the first use for these points, building infrastructure. A player or guild decides to construct a harvesting building, a lumber camp for example. Using whatever method the game offers, they lay the unfinished camp down. Whether the building requires resources or not is irrelevant for this feature, so we'll assume that it doesn't, just to make things a little simpler. However, it does require labor to build. Players click on the unfinished building and choose how many of their available labour points they wish to contribute (I would also require a 'building' skill and have the skill level factor into how effective their labour points are for this task, but that idea is also unneccesary and adds another layer of complexity that I'll gloss over for now). Once the required number of labor points have been contributed, by any number of players, a timer starts. Once the timer is complete, the building is done and production can begin.
Now that the lumber mill is up and running players can choose to contribute their labor points to harvest raw materials, logs in this example. For each labor point, X number of logs are produced. Also, players can choose to contribute labor points to convert the logs into boards, which can then be taken to a carpentry shop and used in other buildings or projects. There would be a cap on the amount of logs that can be produced on a daily basis based on the number of trees in the general area (a lumber mill in the middle of an open plain would not be very productive).
On the opposite end of the spectrum, labor points are also used to destroy buildings. This may be players wanting to tear down their own buildings, or it may be a hostile act against an enemy. To prevent players from arriving at someone's town late at night and tearing everything down before the next morning, there would have to be some artificial limitations on how players use their labor points for destruction. Perhaps a heavy stamina penalty or a hard-coded limit on the amount of destruction a building can receive over time.
The reasoning behind using the labor points for two diametrically opposed actions should be relatively obvious. It's meant to force players to make a choice. They can either use their available labor to assist in building and growing their community, or they can use it for aggresion and destruction; or even some sort of combination of the two. But there will be decisions to make. And those choices have an effect on the world. If your guild is spending all of their labor on tearing down enemy fortifications, then production suffers and perhaps they won't have enough supplies or be able to replace broken items. If your town puts all of their labor into production and town growth, then perhaps a neighbour will start to encroach on your lands by building towers and other fortifications. If you don't take some effort away from production to tear down these intrusions, you might suddenly find that your borders have shrunk.
How will you deal with the issue of mule characters?
Thinking about this question, I would actually say that it's a non-issue. If players have characters whose sole purpose in life is to accumulate labor points, thats fine. The total amount that could be accumulated would be kept relatively small (perhaps a week's worth) and various mechanics could be put in to place to encourage players to skill-up these 'mule' characters so that they are more effective, at which point the line between played character and mule begins to blur. My initial thought would be to have character skills tie in to how effective their labor points are used. A character who is a Master Lumberjack would get more bang per labor point at a Lumber Mill than would a character who has little or no Lumberjacking skill.
In summary, this system is designed to allow players to harvest raw materials, but to also limit the amount of raw materials that can be produced in any given time. It shifts the focus of harvesting towards guilds and communities (since they will be more likely to have the available resources to build camps) while still allowing individual players to have an effect and be able to contribute directly in a meaningful way.