I recently came across an article in the August Edition of Website Magazine about something I've been meaning to investigate for quite some time, but haven't yet researched in depth until now. Foursquare is a mobile application that allows people to "check in" at local businesses and other locations. When a user checks in, they can see if their other Foursquare friends are around, and they can also earn points, badges, and other rewards from Foursquare. Someone can even become "Mayor" of an establishment if they visit the location enough.
So, I went on the Foursquare website and searched in my area (Lone Tree) to see just how popular Foursquare was for local businesses. The answer was... not all that popular. Not a huge surprise, since Lone Tree isn't all that large, and the demographics skew a bit older than I would picture for a fanatical Foursquare user.
Searching for Denver businesses, yielded quite a different story. Below is a screenshot of the Foursquare page for Breckenridge Brewery. You can see that they have a total of 240 people who have checked in the last 60 days - a total of 319 times. Users that arrive at the location can check in and see if they have friends who are present at the Brewery. They can also leave tips for other visitors to Breckenridge Brewery.

Note that many (if not most) users of Foursquare will publish their Foursquare updates through Facebook - so this provides an even larger potential audience exposure for local business owners. As a local business owner, you'll want to be as accommodating as possible to these Foursquare visitors.
How Does This Help Me Market My Denver Small Business?
Well, to start off with, exploring marketing through Foursquare may or may not make sense for your business. I would recommend that retail businesses and restaurants that receive a high amount of traffic - especially traffic that caters to a younger demographic (under 30) - explore Foursquare as a marketing tool for the Denver business.
Claim Your Business Listing on Foursquare
Most businesses that I viewed in Denver may have had a lot of visits, but they didn't actually claim their listings. I would advise all businesses to claim their listings - whether or not they plan to actively market on Foursquare. You can claim your Foursquare business listing here.
Here's why you should claim your business listing (from the Foursquare website)
"you can use foursquare to engage your increasingly mobile customers with foursquare "Specials," which are discounts and prizes you can offer your loyal customers when they check in on foursquare at your venue ... you will be able to track how your venue is performing over time thanks to our robust set of venue analytics"
Foursquare offers a variety of specials to take advantage of - Mayor specials, check-in specials, Frequency based specials based on visits and wildcard specials. Combined with the analytics and the fact that you should always be aware of what is being said about your business on the Internet, you'll want to claim your listing. You'll also want to periodically check your listing as well as tips that visitors are leaving about your business.
Is Foursquare a Great Marketing Opportunity for My Business?
If you have a younger demographic, a retail presence, and a decent amount of traffic coming into your business, you should definitely explore Foursquare. The businesses that have hundreds of checkins and haven't claimed their listings are missing out on an incredible opportunity to market to their patrons and let them know that they "get it" (Foursquare) and that they appreciate their business. Most Foursquare users are likely heavily engaged in social networks and their opinions and experiences reach a large amount of potential customers.