"Your contacts are being synced with iCloud over the air. Your contacts will also sync with this computer. This may result in duplicated data showing on your device."
English:
"We didn't want to implement sync and merge properly, because it's work that requires time and investment, and we were rushing with the release of the new OS and to promote iCloud. That's why it's going to be buggy all the way, beware. However, you can turn the iCloud off and it'll be, hopefully, not worse than it was before."