There is no rigid distinction between authoring and reading. In traditional social or wiki fashion the definition is slightly blurred or fuzzy. That said let's go on and make this distinction.
When you bring in content from a remote site by drag-and-drop of a page-flag, you are able to "read" the content on a single page. However, the difficulty and time it takes implies to the user that this is an act (that is an active authoring action).
Reading happens more passively - there is no conscious awareness of the navigation (clicks), just like with driving, and the content appears fast enough for it to be part of a single reading experience without there being enough time for the thoughts to actively stray.
To take an example in the real world. Turning a page is "reading" - navigating to a bookshop or shelf in a library and obtaining a book is "authoring". The act of assembling a bibliography or reading list.
A transport mechanism is also mainly about authoring. The code is distinct, and provides a loosely coupled service to the federation - an Authoring Service. Should a transporter serve to augment the reading experience, then it is a sign that it should be brought into the federation as a plugin.