Eric Friedman Foursquare’s Director of Business Development posted in Foursquare blog that now location-based social network passed over half a million merchants.

When a business joins foursquare, they get a few main benefits: businesses can offer Specials to their customers, helping them find new ones and rewards their most loyal ones, they can see useful information about their visitors, like what times and days are most popular, and which are your most loyal customers, they get to customize their venue page, making sure the address and map are accurate and adding a twitter handle and description.

This is 100% free. To give an idea what can do merchants here are some examples. Aiming to attract people who are tired of the summer heat, some McDonald’s restaurants are giving free summer drinks with a sandwich purchase or to get more people into their bar at the beginning of the night, PASC bar in Rhode Island is running a Flash Special, where the first ten people each night get a $5 pitcher.

With millions of people out in the world checking in, it’s a great way to stay connected.

Foursquare was founded in 2009. It is a location-based social networking website based on software for mobile devices. This service is available to users with GPS-enabled mobile devices such as smartphones. Users "check-in" at venues using a mobile website, text messaging or a device-specific application by running the application and selecting from a list of venues that the application locates nearby. Each check-in awards the user points and sometimes "badges". Two weeks ago, Foursquare passed a pretty big milestone on foursquare, with over 10,000,000 people in the foursquare community.