How do I sync new droid contacts to deja contacts? Is there an automatic setting for that?

I have Moto Droid 2.1

Last time I hit the "read android" button all my 1400 droid contacts vanished. Any idea why that would happen? Also where does Deja store deja contact info? At one point I had uninstalled it for quite a while then when I reinstalled it, it still had my contacts saved. Thanx