(Before anyone mentions the bug tracker, I can’t access it from this computer so the best I can do is report bugs here)
Viewport snap, (great feature) is assigned to the alt key. Unfortunately “emulate 3 button mouse” is also assigned to the alt key. So those who use netnooks or laptops to run blender (moi) need to use alt to emulate the middle mouse button. Moreover most laptops and netbooks don’t have number pads, so they don’t have shortcuts to viewport controls, making viewport snap even more important on these systems.