Rules.
Lately there has been a discussion about whether posts are on or off topic. Yes, some rules have been established and reaffirmed here.
I look at rules as more like road signs than as rails. Rails are rigid. Road signs are there to keep you between the ditches.
And so we come to the word of the day. One to help with interpreting rules:
dis·cre·tion
noun \dis-ˈkre-shən\
Definition of DISCRETION
3
a : individual choice or judgment <left the decision to hisdiscretion> b : power of free decision or latitude of choice within certain legal bounds <reached the age of discretion>
4
: the result of separating or distinguishing