Final Realms uses properties heavilly.

These are tags on objects/rooms/players that determine how
other things will interact with them.

They affect things like spell damage, unburied corpses
coming to life and other "cute" stuff.

In general coders should NEVER use add_property(), 
however add_timed_property() and add_static_property() are 
reasonably safe to use.

In terms of priorities. timed over-rides static which over-rides
"normal" permanent properties.
