A client-side device is capable of wirelessly receiving user data for the device. The device is capable of removing duplicative user data items among data wirelessly received and data already existing on the device. The duplicative data may be “de-duped” even though duplicative data items may arise...http://www.google.com.hk/patents/US7574444?utm_source=gb-gplus-share專利 US7574444 - Device-side data de-duping
