I never thought about using 1Password with Dropbox, but would you be able to install dropbox on all computers as opposed to a web based alternative?
Sharing passwords is quite important in the development world. When a client gives a company their authentication credentials, it is imperative to keep the data secure while still sharing it with all the developers. The benefit to Passwords.cc with sharing is that the other people who don't have accounts can still view shared passwords without ever registering.
The desktop app we plan on having will be a local system with option of syncing online.