Standards play an important part of not only technology but also society and governments. They establish the definition of what something is and what something is not.
As with all things, standards are of varying quality and there are many types of them. Ad-hoc, or informal standards are ones that people generally agree upon but there may be little or no authoritative definition of what they are. These are prevalent in social standards and generally change over time due to political, social and quite often economic pressures. Sometimes in small steps and sometimes in big ones.
The other side of this is formal standards. Standards where some organization which may or may not have authority over the matter, sets about determining its defining set of characteristics. There are many examples of formal standards, there are literally millions of them around the world.
Standards are generally applied in two ways. Conformance and Validation. Validation is a process whereby some entity decides if a sample of some object or item actually adheres to a standard. Conformance is merely the act of operating or being within the bounds of a standard. A Conforming system can go beyond the boundaries of a standard, however this behavior is outside of the realm of the standard and only systems that similarly behave beyond the boundaries of the standard will interoperate with it. Just because a conforming system can process some input, that doesn't mean that the input actually conforms to the standard. The system may be more generous on its input in an effort to be helpful.
Some standards are designed to accept change and enhancements beyond what is laid out in the standard.