Where do those customized web site icons come from?
In a comment to yesterday’s entry, someone asked about the customized icon that appears in the address bar… sometimes.
There’s actually method to the madness. I was going to write about it later, but the comment (and misinformed answers) prompted me to move it up the schedule a bit. (The originally-scheduled topic for today – the history of Ctrl+Z – will have to wait.)
Each web site can put a customized icon called favicon.ico into the root of the site, or the page can use a custom LINK tag in the HTML to specify a nondefault location for the favicon, handy if the page author do not have write permission into the root directory of the server.
In order for the favicon.ico to show up in the address bar, (1) the site needs to offer a customized icon, (2) you have to have added the site to your favorites, and (3) the site icon must still be in your IE cache.
IE does not go and hit every site you visit for a favicon.ico file; that would put too much strain on the server. (Heck, some people got hopping mad that IE was probing for favicon.ico files at all. Imagine the apoplectic fits people would have had if IE probed for the file at every hit!) Only when you add the site to your favorites does IE go looking for the favicon and stash it in the cache for future use.