https://www.blender.org/manual/modeling/meshes/editing/edges.html
Mark Seam and Clear Seam Hotkey: Ctrl-E-Numpad1 and Ctrl-E-Numpad2
Mark Sharp and Clear Sharp Hotkey: Ctrl-E-Numpad1 and Ctrl-E-Numpad2
I tested Ctrl-E-Numpad1 and it makes an edge/face
I tested Ctrl-E-Numpad2 and it subdivides an edge
I suspect the hotkey should be changed to:
Mark Seam and Clear Seam Hotkey:Ctrl-E-Numpad6
Mark Sharp and Clear Sharp Hotkey:Ctrl-E-Numpad8
Also maybe add a sentence about how the color of the highlighted sharp edge/seam can be adjusted in the Use Preferences->Themes->3D View