Opera, along with Mozilla, announced at a CSS Working Group meeting (minutes) that we would support some -webkit- prefixes. This is because through our site compatibility work, we have experienced that many authors of (especially mobile) sites only use -webkit- prefixed CSS, thereby ignoring other vendor prefixes and not even including an unprefixed equivalent. This leads to a reduced user experience on Opera and Firefox, which don't receive the same shiny effects such as transitions, gradients and the like, even if the browser supported those effects. Bruce Lawson
Another pragmatic, sensible move from Opera.
I saw a lot of commentary on the web and especially on Twitter how this decision will
break the web and encourage lazy web developers to ignore non-WebKit browsers even further. Personally, I don’t see this happening. For one, Opera is only supporting a small subset of WebKit-specific extensions, specifically those with wide-spread adoption and already supported by Opera, albeit under the –o- prefix. As far as I understand, the way this works is, when Opera encounters a compatible –webkit- property it behaves as if the code used the corresponding Opera-specific property.This shouldn’t prevent designers to test sites in Opera, because a) while some –webkit- prefixed CSS properties will be recognized, the rendering will be done according to Opera’s implementation, which may or may not be identical to WebKit’s and b) once you step out of the narrow selection of cross-compatible extensions the rendering will differ just like before. This is just a defensive move to ensure a better experience for Opera users, closer to the original intent of the designer. Ultimately, the end-user doesn’t know or care about the reason why the site looks nicer in a WebKit-browser than in Opera; if he encounters reduced functionality he will probably switch and never come back. This way Opera – and presumably Firefox and Internet Explorer at some point – will have a better competitive chance.
Regardless of this decision, Opera is doing fine in mobile.