Precis of "The End of the Book and the Beginning of Writing"

This chapter is divided into three relatively independent sections:

1. The Program...A claim that writing has superseded speech, and the notion of writing has been broadened to include many different channels/media, including "cybernetics"—which makes you wonder what sort of mid-60s whirring tape drives and punch cards Derrida had in mind. Most interesting for a broadened definition of "writing". Somewhat melodramatic tone which I guess I'll just get used to.
2. The Signifier and Truth...Generally anti the notion of the "transcendental signified", which I take to be something that lies outside the system of differnces that enables a semiotic system. Discussion of where the T.S. has been located historically. Allusions to "theological" notions, i.e. the transcendental signified is God. The notion of God reminds me of Descartes' ontological argument (I think I'm remembering correctly) where "God" ends up getting identified with an infinite set of properties, one of which must be existence, which means he must be real, so there, or Bishop Berekeley's answer to, you know, "Does a tree stop existing as soon as no one is looking at it?" "Ah no, because God is still looking at the tree." The implication seems to be that any attempt to locate a referent outside the system of signification is no less naive than this 17th century God-as-ad-hoc-philosophical-catch-all lameness. Anyway, Derrida then moves on to discuss the presumption that the spoken word has a more direct access to truth than the written word. Like the former can be trusted. Advances this argument by tracing the history of the nature-as-the-speech-of-God metaphor (or book written by God, God being the only written source we can trust). The claim that people have historically accorded speech more authority than writing doesn't ring true to me, but let's go with it. Regardless, Derrida is trying to throw doubt on the notion of some external incontrovertible ground for philosophical truth.
3. The Written Being/The Being Written...An attempt to throw doubt on the notion of ontology in general by making the signified of "being"—both the common verb and Heiddiger's technical term "Being"—murky. I didn't follow this because I don't have the background in Heiddiger. I found it helpful when Derrida referenced "transcendental" and "epochal" signifiers, because it gave me a sense of what the adjective "transcendental" might mean in this context. (Seems analogous to a mathematician's "global" vs. "local".)

Okay, so yeah, Derrida is very opaque, he doesn't define his terms, there are no simple examples, and his prose is an uninterrupted warm bath of abstraction. I knew that would be the case, so I've decided not to find it annoying. I'm also reading for the gist instead of lingering over passages I don't understand. That strategy got me through Ulysses many years back, and I think it applies here as well.