PDF Document Properties - Description

The Description Tab is where most of your search optimized content resides.


File: quality-rater-guidelines-2007.pdf

File = <title> - If a Title is not present (see next), the file name is used by default. This is why it is imperative that your file names are relevant (suggest hyphens as keyword separator) and that you've crafted an optimized document title.
Title: Guidelines for Quality Raters

Title = <title> - This is the single most important element of your PDF Document Properties. This is used as the title in the SERPs. Remember, if this is not populated, the file name e.g. quality-rater-guidelines-2007.pdf is used by default.
Author: Google

This can be a company name or an individual's name.
Subject: General Guidelines for Quality Raters: how to evaluate web pages and search results (2007)

Subject = Snippet - The Subject serves as the META Description for your PDF Document. It is the second most important element after the Title.
Keywords: google, quality raters, evaluation process, web spam

The Keywords dialog is here for a reason, use it effectively. I keep them brief, usually 3-5 primary keywords, no fluff.