"Lineup" refers to the newspaper like arrangement of narrow columns (each of which is a unique page). One nice thing about the line up is that the reader or writer can rearrange them at will, locating relevant content adjacent to the pane (page) in focus.
They are easily moved by placing the cursor to the right and above page the title until a little hand image appears then clicking and dragging the page where you want it, to the right or left.
Interestingly, on can move a page into another FedWiki by dragging (with the same little hand) the page up to the browser tabs and moving over the FedWiki site of your choice and then dragging down into/onto this site and releasing "shift". The page magically is copied into the browser memory associated with the other server. You can fork (copy) it into the memory of the server by clicking on the black flag near the bottom right of the page to be saved.