Title text: Neal Stephenson thinks it's cute to name his labels 'dengo'
goto is a construct found in many computer languages that causes control flow to go from one place in program to another, without returning. Once common in computer programming, its popularity diminished in the 60's and 70's as focus on structured programming became the norm. Edsger Dijkstra's article Go To Statement Considered Harmful in particular contributed to the decline of goto.
Often people learning programming are told goto is bad and should be avoided, but frequently are not given a reason. In this case, Cueball can see no harm in using goto to avoid rewriting much of his program. As a result, he is attacked by a velociraptor. Velociraptor attacks are a running joke (and fear) often expressed in xkcd. The humor derives from the fact that a velociraptor attack is an unlikely thing to happen after using a goto statement.
The title text refers to Neal Stephenson, an author of cyberpunk novels. A label is used in many programming languages to refer to a point in a program that a goto instruction can jump to. The joke is that one of Stephenson's characters in Cryptonomicon is named 'Goto Dengo'.
[Man sits at computer, thinking]
Man: I could restructure the program's flow - or use one little 'GOTO' instead.
Man: Eh, screw good practice. How bad can it be?
Text on computer: goto main_sub3;
[Panel passes in which man simply looks at the computer]
[A raptor jumps into the panel and attacks the man at the computer]add a comment!