Another item which comes up frequently:

A new plot decoration item was introduced. Why is there a limit on how many I can place on my plot.

Every item in the game requires it's own load on the various system resources. From the load on the Community Manager that tells the game system where to place objects within a plot (or in the world), to what is required to draw them on your computer, everything has it's own "load" on the system. We limit the number of items you can place on your plot to something we feel is reasonable based on this variety of factors.