Links will show the links within the paper if you have any. Object will allow you to edit an image already within the document or to covert that image if it can be converted. Web Layout will show you what the document will look like for the web. Print Layout shows the document the way it would look when you go to print it out. Outline will show the document in outline format.
Ruler is a toggle switch.
Document Map displays a list of headings in the document, which can be used to navigate through the document more quickly. Footnotes are those, which are found at the end of each page in a document, and are used to explain, comment on, or provide references for the text in the document. Comments are something that you can insert and allow you to add brief comments about a certain part of the document. Full Screen allows you to work on the document using the full the display area of your screen. Zoom allows you to choose how far or near you want to look at the document.