Those bumps on the F and J keys...

Question: "On my laptops keyboard (QWERTY) there are some ridges on the F and J buttons, what are they for?"


Answer: "People who touch-type (type without looking) use these two ridges to determine the position of their fingers on the keyboard. Touch typists put the index finger of their left hand on F and the index finger of their right hand on J before they type so they know where their fingers are at."
 
Source: Yahoo!