Plots are the spaces in the City Area where you build your Zones in Simburbia. It is important that you lay out what you're building where before you build it because zones built on adjacent plots can affect their Land Value, positively or negatively.
The Plot Indicator is always on the bottom right-hand side of the plot, shown on the Town Map. The Plot Indicator shows whether a plot is powered, unpowered, or was powered and now unpowered. The Plot Indicator consists of the Plot Modification Selector, the Zone Selection, and the redstone lamp and block that shows if there's power.