We want to offer FREE DOWNLOADS via our website (we're an ad agency) of valuable marketing info. We DON'T want the content to be edited & posted elsewhere. Can we protect the PDF so people can PRINT it to take to a meeting, but they can't EDIT it or COPY it?
http://help.adobe.com/en_US/Acrobat/9.0/Standard/WSD012A4E1-51D1-4bcd-BA9F-EF03C6F20BB6.php
There is a print option (None, low resolution, high resolution) along with a ton of other options. The only caveat to note is that: one can always find third paty software out there somewhere that will not honor security on a PDF an potentially allow someone to unlock it and do what they want to it. It obviously would take more work, but it's possible. I've tested this with more recent 3rd party software, and most of them actually *do* honor the security, however - that's a good thing!
If somebody really wanted to adjust your content, they could do screen captures and all sorts of other things, but that's a risk you'd have to take.
All the best ~