Apple had done extensive testing and would never release a 7 inch tablet. The email, dated slightly more than 3 months after Jobs' comments during a quarterly earnings conference call, could indicate a shift in his position on a smaller tablet. Another possibility is that Jobs' earlier comments were a smokescreen designed to hide Apple's true intentions.
Samsung's goal in producing this email in front of the jury could be to show how Apple does indeed keep an eye on what the competition is producing. Outside of the trial, it could indicate that all of the speculation about Apple introducing an iPad mini next month, could very well be true. Most talk about a 7 inch Apple iPad comes from checking out Apple's supply chain and noticing that the manufacturer has been ordering more parts than required for the next iteration of the Apple iPhone. Other talk has centered around a refresh for the 3rd generation of Apple's tablet using a thinner IGZO screen.
Apple is expected to introduce the 6th generation Apple iPhone and perhaps a new tablet, on September 12th.