Staging processes allow developers to accomplish real things and get involved in the creation of standards, testing, feedback, and new use cases.
This staging process reflects the real-life stability of new CSS features.
You can read an inside view of the CSSWG to learn about the official (and unofficial) development stages of CSS specifications. In reality, specifications and browser implementations happen out of sync. For example, there have been stable CSS features missing in all browsers, while other CSS features developed outside the W3C have appeared in browsers. This is too ambiguous for the web development community, and a more accountable process is desired.
“This is a silly idea.”
An Unofficial Draft or Editor’s Draft championed by a W3C Working Group Member. It should be considered highly unstable and subject to change. Stage 0 features are open to ideas and discussion, but may not be considered serious.
“This idea might not be silly.”
An Editor’s Draft or early Working Draft championed by a W3C Working Group. It should be considered highly unstable and subject to change. Stage 1 features are recognized as a real problem, but they may not be tied to any particular solution.
“This idea is not silly.”
A Working Draft championed by a W3C Working Group. It should be considered relatively unstable and subject to change. Stage 2 features are tied to a particular way of solving a problem.
“This idea is becoming part of the web.”
A Candidate Recommendation championed by a W3C Working Group, usually implemented by at least 2 recognized browser vendors, possibly behind a flag. It should be considered stable and subject to little change. Stage 3 features will likely become a standard.
“This idea is part of the web.”
A Recommendation championed by the W3C. It should be implemented by all recognized browser vendors. Stage 4 features are web standards.
“I had no idea what I was doing.”
Any specification that has been rejected or neglected by its editor, or formally rejected by a W3C Working Group.
Recognized browser vendors include, in alphabetical order; Apple (Safari/Webkit), Google (Chrome/Chromium) and Mozilla (Firefox/Gecko).
A champion is the person or group responsible for advocating a new feature to completion, performing the legwork necessary to ensure the concerns of interested parties are identified and incorporated into the proposal.