[mmastrac]

From the FAQ (this is crazy):

Your documents will automatically be entered into the Archive after an initial period of time. You can recall a document from the Archive by opening the document's properties, clicking the Archive Status tab, then clicking the Recall from Archive command. If a document's properties page doesn't have an Archive Status tab, then that document has not yet been placed into the Scribd Archive. To learn how to edit your documents' properties, please see our Writer's Guide.

After a couple months your document will return to the Archive, and you can repeat this process to recall it again.

[tzs]

Or you can go change the global setting so that none of your documents go into the archive.

[mmastrac]

Conveniently not mentioned in the FAQ.

I changed it for my own account only after reading the article. Funny enough, it's an inversely-worded checkbox in there (unlike all of the other options):

[ ] Do not include my documents in the Scribd Archive program. Learn more.