Automatic Publish is probably on of the more obscure features of the Options dialog – and, despite its name, isn’t at all related to the Batch Plot command.
You’ll find it on the Plot and Publish tab of Options, in the lower right-hand corner.
If it’s checked, a PDF or DWF is created every time you save or close a drawing. Which action triggers auto-publish, and which file type is used, is controlled in the Automatic Publish Settings dialog.
As you see, there are options for when to publish (some of which include a prompt before saving), where to publish to, and what to publish. You can also choose the file type, whether or not to include layers, and whether lines that overlap should be merged or overwritten.
I can think of a few of applications for this – general record-keeping, making files available to people without AutoCAD LT – what do you think? Have you ever used Automatic Publish?