We have been working on some SEO improvements to Ceros recently, and one part was looking printing meta data and keywords contained in the PDF of a page as HTML.
This morning I got a reminder from Matt Cutts over at his blog on why spamming google with key words isn't a good idea. Unless like Alex Chiu, you can put a positive spin on it... Although I don't think that would wash with our clients!
For more information check out Google's Webmaster Guidelines and information about keyword stuffing.