While losing context with paper prototype prototyping does happen with paper, it is generally OK to lose that for initial designs. With paper, people do see it as a more informal design and give better feedback overall if you’re using paper prototype prototyping.

paper prototype prototyping article

And when you use the paper format to your advantage and let users really get creative, creating parts of the own designs on the fly, then you really get to see the benefits. You can do so many more things with paper designs - so much more than just measuring completion times and gathering opinions. I have not read Carolyn's book yet - but I did scan it at CHI. I hope that one of her messages goes beyond Huibao's "earlier is better" article - for some design tasks, paper is just plain better than building anything with code. This is a first in a new series for ia/ - "beat reporters" who watch an area and blog it. I volunteered to "join the system" so I will be adding my own comments to Huibao's articles. for any  paper prototype prototyping opinions.