Sysop prerogative is the right that an owner of an online community has to take whatever actions they wish in order that the community functions the way they wish. In common law counties it is understood that someone can do whatever they want unless they give that right way or it is taken away from them by a superior authority, such as Parliament, in the case of the United Kingdom (UK). It can therefore be expected that the systems operator (sysop) who owns an online community is free to operate their community under any rules they want that has not been taken away from them by statute. After all the community is surely their property which they can use and dispose of in any way they choose?
However, with each right or freedom comes certain duties and obligations, something which is enshrined in the European Convention on Human Rights. This convention, like the Treaty on the Functioning of the European Union, places obligations on nation states to guarantee certain rights and not to interfere with the enjoyment of these rights except where they conflict with other rights or duties. This means that sysop prerogative may be both guaranteed and limited by European Human Rights Law.
Sysop prerogative can be used for instance to ban users who don’t participate, known as lurkers, some of whom make up to 90% of activity according to some sources.