It's not really a separate pipe, its's simply the bits of information that tell the dumb pipe where/how to run. For example, the Google Docs connector knows generically how to connect to a hypothetical person's Gdocs account, but the auth credentials provide the information that is required to connect to a real person's account.

A "smart pipe" is actually a lot more like the Collections. They bring data in from sets of similar Connectors (dump pipe) and collect, de-dupe, and normalize it.