Retrevo, an electronics marketplace, randomly surveyed 1,000 of its users before the iPad announcement and then again after the iPad announcement. They then took this data and graphed it using a few pie charts. Apparently Retrevo users have changed their minds from before the announcement to after the announcement. Fewer are willing to buy the iPad, or even think that they need it. Since they only surveyed their users, the data may not be indicative of the general population of the United States. Such mistakes have been made before, with hilarious results.
Your comparison is a fail because the 26% increase in those who have heard of the iPad is negated by the 27% of those who have heard of it and want to buy one (3% to 9% increase yields a difference of 6%) and those who are interested in buying one after getting more information on it (21%) Combined, that’s 27% – a 1% change in favor of those who want to buy one.