You, the customer, are actually starting to initiate the advertizing to yourself.
Online check-ins, as a trend and use-case, have created a remarkably compelling opportunity for offline merchants to interact with consumers who are in the store before the sale happens. When you announce you’re at a store or restaurant by checking into Foursquare or Facebook Places, for example, your experience can be shaped and molded in compelling ways.
This is precisely why check-ins are incredibly powerful—they give the offline merchants an opportunity to shape your behavior before you buy or consume. Unfortunately, check-ins alone provide little value to merchants in the absence of contextual data about you. And checking into a place definitely does not equate to liking it. Imagine how many restaurants you visit, then consciously decide to never return to. Without a feedback loop this context will be used erroneously for future offers and recommendations.