Apparently those of us without SO's on our Kindle 3's can now opt in and out on demand.
I found this little blurb next to my K3 on manage my devices on Amazon.com:
The Kindle is currently not subscribed to Special Offers.
By subscribing to Special Offers, you will receive the same great Kindle experience, plus Special Offers & Sponsored Screensavers that display on your Kindle's home screen and screensaver -- they don't interrupt reading.
You can choose to unsubscribe at any time.
I guess by paying $30 extra for no ads, we have the "luxury" of opting in and out.
Once I get my non-SO KT, I think I'll switch my K3 to the special offers
