Well, in Ecco, you can make a "replica" of any .eco file, and move that replica to any other computer.  From that point, any changes made to the original file, or to any of the replicas, are recorded in a separate "master file" with an .ecg extension.  The changes are kept in the master file until they have been replicated in the original file and all the replicas.  Synchronization can be done manually from the original file or any replica, by means of export/import files. 

 

Synchronization can also be done "online" - i.e. there is a network connection between the computer with the replica file and the computer with the .ECG master file.  In this case, any changes in the replica file are instantly received in the master file.  If multiple replicas are open at the same time on multiple connected computers, changes made on one replica are instantly replicated on the others.  It works really well.

 

Dropbox is great, but what if you're running IQ on computer 1 and computer 2 at the same time, with the  IQbase file in the Dropbox open at the same time on each computer, and changes are made to the file on both computers?  Not sure if Dropbox can make the appropriate changes on both computers without losing some of the changes, or corrupting the file.  The Ecco system understands the Ecco data structures, and can handle this situation very well.