If you're using IE7 or Firefox, you've probably noticed more and more websites using favicons.
We started deploying them on client sites about 6 months ago as we began noticing the increased use of the mini desktop graphics.
Now, the proof.
As we wandered through a live hit weblog the other day it was apparent that some search engines are now looking for them as part of their algorithm.
While we're not sure if having a Favicon says your site is really 'relevant', it does say you're up to date with the technology trends.
If you're not using them, add them to part of your SEO toolkit.
If you don't know what a favicon is, just do a search. You'll find everything from descriptions to free online favicon generators!