(w3c)
At the moment CSS3 is in a transitional stage. Browsers will constantly need to be updated in order to stay current. Outdated browsers will still be the choice of some users. In the meantime we will need to pick and choose which elements of CSS3 we would like to incorporate into our sites.
Vender Code
For the time being in addition to the normal declaration you need to add vendor code in order for the browser to read CSS3
Vender Code
Browser
-moz-
Firefox
-webkit-
Chrome & Safari
-o-
Opera
-ms-
Internet Explorer
Over time the different pre-fixes will no longer be required.
Example
Styles for rounded corners would be written like this: selector{
-moz-border-radius: 20px;
-webkit-border-radius: 20px;
-o-border-radius: 20px;
-ms-border-radius: 20px;
border-radius: 20px;
}
User's Choice
Web Designers should no longer be worried about whether or not all users get exactly the same experience. As long as we make sure that they all get the same information and when necessary the technology they need to complete a task we can go ahead with incorporating some of the new bells and whistles knowing that they will not be seen by all.
We have spent too long designing for the capabilities of the lowest common denominator (e.g: IE6).
The user experience should now be determined by the user's choice of browser. If the user wants a first class experience they need to use a first class browser. It's theirs for the downloading.