We search your contacts for other friends using Foursquare who you may want to connect with, but we do not store the information from your phone book and never have (that’s private to you!). We simply match the numbers and email addresses against users on Foursquare. We do not share this information with anyone else and do not save copies of this search. All the information is encrypted when it moves between your phone and our servers, meaning it’s even more secure.
You can also opt out of the search when prompted from the 'Find Friends' screen.