One reason this is a big deal: Opera now supports CORS [1]. Until now, it was the only significant browser that didn't. (Even IE did, albeit - of course - in

One reason this is a big deal: Opera now supports CORS [1]. Until now, it was the only significant browser that didn't. (Even IE did, albeit - of course - in its own special way.) [1] http://en.wikipedia.org/wiki/Cross-origin_resource_sharing http://en.wikipedia.org/wiki/Cross-origin_resource_sharing - secure cross-domain AJAX without hacks like JSONP, so you can do POST requests, set headers, etc.