The guys from Socialbakers made an useful Facebook Shortcuts Infographic with Windows and Mac OS X specific keyboard shortcuts.
If you want to speed up your actions on Facebook: to respond to a friend, to open links, to go on the profile page, account settings and much more, you can see Facebook Shortcuts in the Infographic below .
Note: If your computer does not contain a numerical keyboard (or you don’t have English set as primary language) you will have to press the “Shift” key for each of the keyboard shortcuts containing figures.