Its interesting to note that many folks don’t really know what it takes to get a feature in a browser and how all the browsers align with how a feature will work. You would think there is a cabal of browser vendors sitting in a smoke-filled room coming up with how features will work.
Then, when a specification has been discussed and worked out, typically browsers will begin to support it and then when it has had some real-world testing, then it will reach its final destination in the process which is considered a Candidate Recommendation.
Now, this doesn’t always necessarily work in a waterfall-like model. Sometimes a browser vendor will go ahead and do an implementation even though a specification has not gone through the full process. There is nothing that stipulates that a browser vendor must wait for a specification to reach Candidate Recommendation. In these instances, browsers will typically implement a feature with a vendor-prefix but still work through the web standards process and even change its implementation.
If you are intrigued by this process (as you can imagine, it is much more complex than my simple explanation) of how a feature becomes a standard, I recommend checking out the FAQ at the Web Standards Project.
Also, I would be remiss to not also let you know that we have a great write-up of how you can set up your site to take advantage of web standards. Also, make sure that you check out the latest Internet Explorer 9 as well as the upcoming Internet Explorer 10 that continues to implement web standards on par or even surpasses other browsers.