We just set up Backup Assistant on our Droid X to back up the Contacts (that aren't available when you mount the Droid X as a USB device, unfortunately...I wish you could just drag your Contacts to your computer).
Right after doing the backup (using Sync Now on the Droid), we noticed that there weren't as many contacts on the Verizon web page as on the phone. Then, we edited one of the contacts on the Verizon page (added a birth date and a note) and pressed the Sync Phone on the Backup Assistant page. It processed for a while, said "Sync Successful" on the Droid, but then, on the phone, that edited contact is missing. It's still there on the Backup Assistant page. We waited overnight for an automatic backup: it's still not there.
OK, so then we went to Google, which is set up to sync Contacts on the Droid; we were unaware of that feature on Google. But the Google contact list is even smaller than the Backup Assistant list.
We've followed all the procedures in the Droid X manual, and the other things recommended on the Support pages. No change.
Any advice?