Book Survey

Jumping in here! :) To answer your question, the difference is simply that the + button that you see in both instances is a jumping off point for two different types of actions.

In the box at the top of the feed or at the top of the list view for a topic, the + option offers you the option to make your post a poll, a question, or a link.

When you open up what we call the "full post form" or article editor, the + button does appear again once you press enter and start a new line, but in this case it offers the option to add something to your post (a photo, an embedded video, or an attachment or file).

Hope that helpful—and please keep the feedback coming! It's super helpful for us to understand where things might be confusing.