ICS introduces the possibility to share an application via Android Beam using NFC, and as far as I understood if an app is opened on deviceA it will automatically be started on deviceB (if it's already installed on it, otherwise the Market app will open) when the devices are close enough and a user "touches to beam" it. Is there a way, inside the launcher Activity, to detect if it has been started because of a NFC message or because of a user interaction?
Only NFC Intents are started when a beam occurs. These are ACTION_NDEF_DISCOVERED, ACTION_TECH_DISCOVERED, or ACTION_TAG_DISCOVERED. Check out the beaming section of the dev guide for how to handle beams: http://developer.android.com/guide/topics/nfc/nfc.html#p2p
In case the Android Beam (or NDEF) message contains an Android Application Record, http://developer.android.com/guide/topics/nfc/nfc.html#aar, the resulting Intent to start the app will not be of the action ACTION_NDEF_DISCOVERED, but ACTION_MAIN. This method can be used to launch any app, including apps that do not filter for NFC intents.
来源：https://stackoverflow.com/questions/8974001/detect-when-application-is-started-via-nfc-in-ics