InformAction Forums

Quite a few websites, including prominent ones such as YouTube, have begun to annoy you in new ways, completely without scripts. The culprit is called CSS3 animations and transitions.
Even with scripts globally disabled, this is a harmless example of what websites can do: http://devfiles.myopera.com/articles/9132/sun-rise.html. And the only way to disable it in Firefox is to turn off CSS altogether (View > Page Style > No Style). If it's technically possible, I'd like to see NoScript remove CSS3 animation and transition features as well.

Is there a way for this to become an actual threat? Eg advanced phishing of some kind?

With userContent.css you might be able to override all these annoying stuff I guess, theoretically might break some sites though.

That is one particular way.
You could block http://devfiles.myopera.com/articles/9132/sun-rise.css.