Toggl use a favicon animation to show when a timer is running or not, but it's as simple as red icon on, black icon off. More distractingly they also animated the title to show the timer, but thankfully there's now an option to disable that.
I find it pretty distracting having anything in my browser titles animated, just catches your eye now and then and breaks my train of thought.
A bit like the annoying ripple effect on buttons and hovers in Google's material, it's excess visual clutter that my brain, at least, decides it needs to pay attention to.
1% or so and from my feeling that's way too many. If you haven't experienced them you don't know how f*n annoying it is to have a tab just outside of your vision range to always do something. You constantly move your attention there.
I've seen zero animated favicons. I'm wondering if it's a "feature" that doesn't work on Linux. The URL bar doesn't even display favicons anymore, although they show up without animation in bookmarks.
http://www.p01.org/releases/DEFENDER_of_the_favicon that somebody linked to shows that the animation does indeed work in the Linux version of Firefox. Weird that I've never seen one before, but now that I've seen it, I don't want to see another.
For an audio player I used it to display song progress, and if that wasn't so choppy I'd love to do actual audio visualization, too. And I just had an idea I will actually try: display website hits in the last 16 minutes or seconds while the tabs with the stats is open but not focused.
I'm not saying it's super important, but I also don't find it useless. I'm all for 60/120 fps favicons, even if I had to set a config flag to enable them.
And that's precisely why you shouldn't be using them. We developers are some of the worst people at understanding what's actually important and what's not to a user's workflow.
I assume you are that user-base... I upvoted and then had the horrible thought that you might be making your significant other wade through animated gifs before she can use your Intranet only coffee pot every morning.
I find it pretty distracting having anything in my browser titles animated, just catches your eye now and then and breaks my train of thought.
A bit like the annoying ripple effect on buttons and hovers in Google's material, it's excess visual clutter that my brain, at least, decides it needs to pay attention to.