I've been using Plaxo for quite a while to keep contacts in sync between gmail and comcast. Looks like Plaxo is shutting down soon. First isn't plaxo owned by Comcast? And will there be a new feature to replace what Plaxo did? Or another way to sync?
When you are migrated to the new format, the address book should be migrated as well. I can find no way so far to sync the Comcast address book with any other in the new format.