This may apply not sure, but there were TONS of duplicate contacts and it was facebook!
"If you have the 1.3.1 facebook, it's likely the culprit. I had contacts that had hundreds of duplicates, they manifest themselves as linked contacts.
Log out of facebook, clear the facebook data, and the duplicates will go away. If you log back into facebook set the contact synchronization option to not sync, it should work until they come out with an update." - jeffs
When you log out of FB, it will warn you that all data will be removed (YAHOOO) so go ahead. Then log back in and select to NOT SYNC. It worked and my contacts are WAYYYY cleaner!