YouTube - The favicon changes based on whether the video is buffering, playing, or paused.
/via tmercswims

YouTube - The favicon changes based on whether the video is buffering, playing, or paused.

/via tmercswims

Gmail - Incompatible versions of Internet Explorer show a damaged envelope as the favicon.
/via Eric Hansz

Gmail - Incompatible versions of Internet Explorer show a damaged envelope as the favicon.

/via Eric Hansz

Apple - The favicon was at half mast during the anniversary of Steve Jobs’ death.
/via ceenk

Apple - The favicon was at half mast during the anniversary of Steve Jobs’ death.

/via ceenk

Colllor - The favicon changes to match the chosen color
/via Tom

Colllor - The favicon changes to match the chosen color

/via Tom

Flickr - The favicon turns into a live indicator showing the progress of the upload.
/via nWODT_Cobalt

Flickr - The favicon turns into a live indicator showing the progress of the upload.

/via nWODT_Cobalt

Mixcloud - The favicon indicates whether the music is playing or paused.
/via Victor A. Leão

Mixcloud - The favicon indicates whether the music is playing or paused.

/via Victor A. Leão

Chrome - Accent colour on most visited thumbnails is pulled from the site’s favicon.
/via Andrew Procter

Chrome - Accent colour on most visited thumbnails is pulled from the site’s favicon.

/via Andrew Procter

Google Calendar - Favicon displays the day of the month.
/via Alexis

Google Calendar - Favicon displays the day of the month.

/via Alexis

Campaign Monitor - The favicon shows a closed email when logged out, and changes to an open one when logged in.
/via @iamjamie

Campaign Monitor - The favicon shows a closed email when logged out, and changes to an open one when logged in.

/via @iamjamie

Gmail - Favicon shows the number of unread messages you have. 
Read more here
/via Adrienne

Gmail - Favicon shows the number of unread messages you have. 

Read more here

/via Adrienne