Title text: "This is the reference implementation of the self-referential joke."
Douglas Hofstadter is an American author who has written several books about philosophy, mathematics, and science. He is perhaps most famous for his book Gödel, Escher, Bach which explores "strange loops," or self-referential systems. "Meta-" is a Greek prefix meaning "outside" or "beyond." As an adjective, "meta" informally refers to anything self-referential, like the last clause of this sentence. An example of the use of such a term can be found in 1313: Regex Golf.
At first reading, the six word autobiography in the second panel, "I'm So Meta, Even This Acronym", may seem unfinished, however the clue is in the final word. An acronym is an abbreviation formed by the initial letters of a series of words, and reading the first letter of each of the six words in order yields "IS META", completing the sentence and setting up the self-reference.
This comic may additionally be a reference to the meme "explain <whatever> in six words", which was making the rounds at the time.
In the title text, a reference implementation is, broadly, an example of how to implement some feature during the software development process. In this case the feature is a self-referential joke, and the sentence itself is, correctly, self-referential.
Hofstadter has been referenced before, in the title text of 555: Two Mirrors and 608: Form. Furthermore his famous book has been directly spoofed in the title of 24: Godel, Escher, Kurt Halsey. Finally the self-reference reference ("IS META") is also a typical concept used most famously in 688: Self-Description but also very early 6: Irony in 33: Self-reference and in the title text of 442: xkcd Loves the Discovery Channel.
- [Cueball sits at a desk, working on a laptop. Megan approaches the desk and picks up a tiny book.]
- Megan: What's this?
- Cueball: Douglas Hofstadter's six-word autobiography. After all those 700-page tomes, I guess he wanted to try for brevity.
- Megan: Huh. Let's see...
- [Close up of Megan, reading the tiny book.]
- Book: I'm So Meta, Even This Acronym
- [Full shot of Cueball and Megan again. Megan looks down at the tiny book in her hand.]
- Megan: ...whoa.
- Cueball: I think he nailed it.