When people talk about near-field communications (NFC) chips in phones, they usually bring up mobile payments. But NFC chips, which are already in some Android phones , can be used by other apps besides payments (which won't take off as quickly as people expect anyway). At Google I/O this week, NFC apps will be highlighted. Foursquare will allow Android users to check in by swiping their phones near posters with NFC chips . Also just in time for I/O, Hashable's Android app now supports NFC features as well. Android users can swap contact info via NFC, and also check into the same activity with someone, like #dinner or #drinks.