That's an interesting approach, but I wonder if it isn't subject to "thrashing" as soon as you start dealing with documents that are edited in more than one pla

That's an interesting approach, but I wonder if it isn't subject to "thrashing" as soon as you start dealing with documents that are edited in more than one place. For instance, imagine that you have a laptop L and a desktop D. You edit shared document X in your "actual files" folder on L. Version 2 of X is saved on L, and you currently have version 1 of X on D. 1.) Dropbox happens to notice that X needs to be updated from v1 to v2 on D. Dropbox updates X to v2. 2.) Skydrive has not yet been notified of the changes to X. It changes X back to v1 for you on D. 3.) Dropbox notices that X has been modified on D. It sees that the new v1 X has an updated timestamp, so it assumes that this is a better version of X. Dropbox saves this as v3 (which is identical to the original v1). 4.) Dropbox pushes the v3 change to L, erasing your v2 work. Oops! Basically, unless every synchronization service follows precisely the same protocol, you're gonna have a bad time.