On Everything2 a writeup is the text of an individual user's contribution to a node. Users on Everything2 also refer to them as articles. What you are reading right now is Virgil's writeup for the node titled "writeup." A user can contribute one writeup to a node, with a character limit of 64k.
To create a writeup, please read How do I submit a writeup of my own?.
Revised October 12, 2012