Favicons have been spotted in Google Adwords Ads!
They have been seen appearing on certain ad units in text based ads offering additional triggers for brand awareness to your potential customer base.
You can see one taken from lnky.eu below.
I also have seen another one appear for WebMeUp in the last few days, I certainly like this approach as it may also help more websites move away from the generic favicon images such as the hosting companies logos or server control panel logos (Yes Bluehost and Plesk; im referring to you!).