The followings are form [here]
- Honoring key web tenets – The Web favors stateless interactions which do not saddle either party of a data exchange with the responsibility to remember what the other did or expects. Doing otherwise is a recipe for extreme brittleness in implementations; it also raises considerably the development cost which reduces the reach of the standard itself.
- Flexibility in its support of popular media formats and codecs as well as openness to future innovation– A successful standard cannot be tied to individual codecs, data formats or scenarios. They may soon be supplanted by newer versions that would make such a tightly coupled standard obsolete just as quickly. The right approach is instead to support multiple media formats and to bring the bulk of the logic to the application layer, enabling developers to innovate.