Bruce Lawson via .netmagazine:

Opera, along with Microsoft and Mozilla, announced at a CSS Working Group meeting that we would support some WebKit prefixes. This is because too many authors of mobile sites only use the WebKit-prefixed version, and not even the standard, unprefixed one, when it is available. This leads to a reduced user experience on Opera, Mobile Firefox and Mobile IE, which don’t receive the same shiny effects, such as transitions, gradients and the like, even if the browser supports those effects.