Foursquare Helping Businesses?

Fourquare, a location-based social network, provides new tools for businesses to better track customers.   So far 30 businesses are testing the real-time data and will quickly be rolled out to 900 businesses.  The data will provide businesses with an opportunity to customize customer promotions.

http://bits.blogs.nytimes.com/2010/03/09/foursquare-introduces-new-tools-for-businesses/?ref=smallbusiness

Foursquare users have the option to keep their information private.  Will you opt-in or opt-out?