One of the most popular definitions of the term “open standard”, as measured by Google ranking, is the one developed by Bruce Perens. His definition lists a set of principles that he believes must be met by an open standard:

1. Availability: Open Standards are available for all to read and implement.
2. Maximize End-User Choice: Open Standards create a fair, competitive market for implementations of the standard. They do not lock the customer in to a particular vendor or group.
3. No Royalty: Open Standards are free for all to implement, with no royalty or fee. Certification of compliance by the standards organization may involve a fee.
4. No Discrimination: Open Standards and the organizations that administer them do not favor one implementor over another for any reason other than the technical standards compliance of a vendor’s implementation. Certification organizations must provide a path for low and zero-cost implementations to be validated, but may also provide enhanced certification services.
5. Extension or Subset: Implementations of Open Standards may be extended, or offered in subset form. However, certification organizations may decline to certify subset implementations, and may place requirements upon extensions (see Predatory Practices).
6. Predatory Practices: Open Standards may employ license terms that protect against subversion of the standard by embrace-and-extend tactics. The licenses attached to the standard may require the publication of reference information for extensions, and a license for all others to create, distribute, and sell software that is compatible with the extensions. An Open Standard may not otherwise prohibit extensions.