Question

Does dropbox have a way of notifying when a file changes i.e arrival of new uploads or a file has changed.

Answer 1

As Kannan points out, there’s a new API endpoint called /delta that’s better than polling or RSS.

This can also be used in conjunction with the /longpoll_delta API endpoint :

A long-poll endpoint to wait for changes on an account. In conjunction 
with /delta, this call gives you a low-latency way to monitor an account 
for file changes.