When you connect another app to Foursquare, the app gathers information from both of your accounts (for example, it might pull from both what you’ve shared with Soundtracking and with Foursquare), and sends you a personalized message after you check in based on this information, if relevant. The messages will only appear one at a time on the post check-in screen, and might not appear after every check-in (only when it makes sense!). You’ll also have the option to tap on the message to view more info, or to hop into the other app. Remember that the more active you share things with the connected app and Foursquare, the more interesting your post check-in messages will be!

Your Foursquare friends will be able to see which apps you’ve connected to via their activity stream, but *only you* will be able to see the messages from the apps on your post check-in screen. Additionally, no information regarding your connected apps will push to Twitter or Facebook (unless you’ve chosen to share information to those channels within your settings for the other app).