I am interested in making this a comprehensive listing of for all the various situations where one might need to engage in public deliberations or advocacy on free software issues, but I've started with the modest goal of dismissing Microsoft's inane disease metaphors when discussing the GPL. This was initiated (as far as I know) when Craig Mundie (a vp at Microsoft) was quoted as calling free software (he misidentified it as "open source") "unamerican" and referring to the GPL as a "virus".
So, here goes.
Talking points regarding Microsoft's assertion that the GPL is viral.
links: linux-advocacy faq