A great reminder that you should be marketing your participation on FourSquare in the real world

Are you using FourSquare to promote our business?
How do you ensure people to learn about your specials and promotions or rewards for the Mayor?
Here is an example of a business promoting they are on FourSquare with a sticker in their window.
It's a great reminder to integrate your marketing online (on the web or mobile platforms) and offline.
What other examples have you seen?
