Foursquare recently redesigned its app to focus less on the act of checking in and more on an activity feed of what is going on around you. The goal is to be the best, most personalized guide to any city or neighborhood. Today it’s giving the nearly one million merchants who have claimed their venues on Foursquare a way to communicate with their best customers in real time, by letting them post what is calls local updates into the feeds of their loyal patrons.