Google counting down, but to what?

Ever since I started running ads using Google's AdSense program, I've noticed that they list their normal "Ads by Google" string with a lot more o's than necessary. I figured it was some sort of inside joke, and thought nothing of it. Others have noticed the same thing, except that the number of o's appears to be shortening ... sort of like a countdown.

I wouldn't be a bit surprised if Google used this as a way to put something like a countdown to a product launch in plain-sight, but it's a bit obscure if it's truly the case. Is it AdSense-related only, or something more significant. I've also noticed that some sites have more o's than others ... there doesn't appear to be any consistency. I wonder what it all means? Probably nothing, but it's certainly curious ...