There are several social media check-in applications that you can use to earn points or miles or save you money.
Foursquare – an app downloadable on your iphone or android where you can “check-in” to places such as restaurants, hotels, airports, stores, bars etc. To check-in you must be in the proximity and sometimes places will have specials that you can “unlock” for checking in. For example some stores will give you a % discount, some restaurants will give you a free appetizer, and this past weekend (thanks to PointstopointB for sharing the tip) I was able to receive 1,000 Club Carlson points for checking in to the Radisson LAX, leaving a tip or photo, and showing the front desk. I like free points :)
Top Guest – After you register for this program online, it can be synced to your Facebook and Foursquare accounts. For certain check-ins, you are able to earn hotel points or airline miles. The participating programs are Priority Club, Hilton, Virgin America, etc You must give them your account #s in these programs in order for you to get points credited. Many people have had their TopGuest account closed due to abuse of over checking in to places so I’ve generally have stuck to only places I’ve actually been and have had no issues.
TripAnomaly – A more recent program that is currently only partnered with Delta. After registering for this program online, you can earn points by checking in to a Delta location (ticketing counter, hub, lounge, gate, etc) on Facebook. Then you go to the Tripanomoly website, login with your facebook and verify your check-in to receive 80 Delta points. I’ve tried to do 2 check-ins in one day but the website said that I needed more time between check-ins to receive points. (I’m guessing this means only one check-in a day?!)
Bckstgr – a beta program that is partnered with United. To register, you login to your United account through the bckstgr website. You then connect your foursquare, twitter, and or facebook account with bckstgr. You then perform certain steps depending on the place ei, check-in and snap photo, tweet something, FB checkin (currently only Chicago & NY places) to earn miles. These miles will be deposited into your United Mileage Plus account within 24-48 hour (mine posted quicker than that). These miles can also be used to bid on experiences. Hopefully they will be adding more places to "check-in" to make this more lucrative.