I've been offline for the last few hours, just came back to start picking through the notes. I like this Mickey Mouse analogy most of all the ones I've seen so far. Concise and relatable (and accurate).
The shoplifting analogy seems more immediate and straight-forward to me. I understand that the shoplifting analogy equates piracy with theft but the distinction isn't really all that relevant to SOPA. Uncle Art probably equates piracy with theft anyway, so why fight the battle on two fronts?
One final point on this, by indirectly conceding the piracy/theft point you're less likely to step out of alignment with Uncle Art thus making it easier for him to agree with everything else you say. :)
P.S. I know we're all probably focusing too much on that killer soundbyte but I do think it was the missing ingredient. :)
If we abstract analogies too far, I worry that people will ignore them. I tried to leave Uncle Art with very few dots to connect by only changing the "host" business in my analogy.