I assume the parent comment proposes land value tax as a replacement for existing property tax schemes. In other words, instead of taxing the value of the land + whatever is built on it (current system in most parts of the world), you only tax based on the value of the land, regardless of what is built. Such a system would incentivize using the land as efficiently as possible, as that part is not taxed.

If you have prime real estate in the center of a city but that is undeveloped, currently developing it increases your tax. In a land value tax system, that land would presumably be taxed higher, but tax would not increase if it is developed, therefore incentivizing the owner to actually use it.