Hah, I actually meant the little icon displayed in the tab, usually called a "favicon" (and usually located on the root of the website as favicon.ico, but I don't know about an animated version).
I do generally have a lot of PG tabs open as I tend to open up all the DS news in the newsletter, one of the few such mailing lists I'm subscribed to. Unfortunately this has the effect of usually 6-10 green icons animatedly turning into blue icons every few seconds, even whilst I'm reading my email in another tab or browsing the news in another.
I really do think that this is exceptionally bad form; the only big website I've heard of having this "feature" is DHL (the commercial US postal service), and I only know that because there are numerous complaints around the internet concerning this.
http://www.webmasterworld.com/forum21/11870.htm -- discusses how to achieve an animated favicon, and annoyance enters the discussion: perhaps if you took the original poster's advice and only animated 1-3 times it would be more acceptable.
http://lifehacker.com/5036881/how-to-bl ... d-favicons -- speaks for itself, and perhaps the prospect of people installing adblocking software just to get rid of the irritation I'm complaining of, might nudge you into action (this is not a threat nor a statement of intent; I merely point out that people do consider these options)
http://forums.mozillazine.org/viewtopic ... 3&t=665596 -- more people wanting to stop or remove animations in their tab bar
http://radar.oreilly.com/2005/12/does-f ... rld-r.html -- as far back as 2005 people were noticing and being annoyed by them
Google does not have one. Facebook does not have one. Microsoft does not have one. Reddit, Digg, Slashdot, Ikea, eBay, The Times Online, The New York Times, the Guardian, YouTube, Blogger, GAME, Abandonia, DailyMotion, Wordpress, Nintendo: none of these sites have an animated icon.
It's not a popular thing to have despite having been available for at least three years; there is a reason for this. It's REALLY annoying.