Have you ever wondered about tweets like, “I just checked in at The Home Depot (with 7 others) 4sq.com/UxfgH“? Or why people seem to grab their smart phones when crossing the threshold of a restaurant, tap the screen a few times, and quickly file it away?

Popular among customers and business owners, location-based check-in programs are a growing niche segment of both the social and app markets. Below are profiles for the 3 most popular check-in apps:

FourSquare

Quite possibly the most well-known location-based check-in app, FourSquare offers benefits for both consumers and businesses. Customers use an app on their smart phones to check in to an establishment when arriving. Repeated check-ins to the same location may earn you the title of “Mayor”, while several check-ins at similar types of businesses can earn you badges such as Bento, Hot Tamale and Bookworm.

Business owners can create specials to reward customers who check-in, and have (free) access to valuable consumer insight data like most frequent visitors, times of day for checking in, and customer gender breakouts with account creation. Also, it is possible for FourSquare app users to share their check-ins via Twitter and Facebook.

Yelp

The “customer competition” vibe is also strong with Yelp, as customers can vie for Duke/Duchess, Baron/Baroness and King/Queen of a city titles. In addition to checking in upon arrival and sharing with Twitter and Facebook friends, Yelp’s tool focuses on customer ratings and reviews.

The Yelp community is also vibrant beyond just a smart phone app, over at Yelp.com. Yelp has several city-specific representatives who run local events and invite those Yelpers who have attained “Elite” status to attend.

Much like with Facebook, Yelp business registrants can claim their free account and set up customer deals.

Facebook Place

The most basic of these 3 check-in tools, Facebook Place check-ins require the use of the Facebook app and simply are a way to let others know where you are. Unlike FourSquare and Yelp, there are no incentives tied to checking in.

All 3 location-based check-in services allow customer check-ins to a store or restaurant that has not set up its own profile or page. Business owners should claim their Place in order to manage their own business profile information like address, contact information, hours of operation and a profile image.

Have you as a customer use any of these check-in apps? Have you as a business owner claimed your profile or set up deals?