The Important Field
The Important Field
[A soldier with a green military hat, with an black emblem on the front, is sitting in an office chair typing at his computer. Sounds are shown when he types, and the message he reads on the screen is shown above with a zigzag line coming from the computer screen. In the first panel he only uses one hand on the keyboard.] Computer: Welcome to the missile launch web interface! Click
[Same setting but the soldier types with both hands.] Computer: Enter the target's coordinates. Type Type
[Same setting as previous panel.] Computer: Enter your email address for our records. Type Type
[Same setting except the soldier has stopped typing.] Computer: Enter your email again, to ensure you typed it correctly.

In this comic, a soldier with a green hat with a black emblem on the front, is using his computer to access an online web interface to launch a missile at a target. The joke is that even though the interface only asks him to enter the target coordinates once, it asks for his email address twice, even though the coordinates are by far the more important detail to get right (launching the missile at the wrong target could result in a disastrous loss of life or property damage).
It is common for online interfaces to force users to type certain details twice, as a form of redundancy checking to ensure that the user really has entered the correct details and hasn't made an error. Some forms even go the extra step of preventing the user from copy-pasting into the second field, which would render it useless as a redundancy check.
This is usually done for email addresses and when creating new passwords, which are used to identify and authenticate users, and are therefore important to get right.
In the title text, Randall suggests that the presence of redundancy checks can give you an interesting insight into what things people deem to be important. He gives a (supposed) real-life example of a merchant that requires only one form of ID in order to buy a gun, but two forms if you want to pay for it by check - suggesting that the seller is more worried about the safety of their money than the potential danger of giving a lethal weapon to someone untrustworthy.
[A soldier with a green military hat, with an black emblem on the front, is sitting in an office chair typing at his computer. Sounds are shown when he types, and the message he reads on the screen is shown above with a zigzag line coming from the computer screen. In the first panel he only uses one hand on the keyboard.] Computer: Welcome to the missile launch web interface! Click
[Same setting but the soldier types with both hands.] Computer: Enter the target's coordinates. Type Type
[Same setting as previous panel.] Computer: Enter your email address for our records. Type Type
[Same setting except the soldier has stopped typing.] Computer: Enter your email again, to ensure you typed it correctly.
