Some of the hidden messages are revealed through a font that produces tiny printed text that can only be viewed with a magnifier.
Other hidden messages are revealed by shining a UV light source, the Discovery LightTM, on certain areas of the book. Below is a demonstration of the flourescent text in action.
We also put variable data into the books we were displaying at the show. To demonstrate that the books can be personalized for the child that will receive them, we put an assortment of different sample names in the giveaway copies of the book.
Kids aren't the only ones who like personalization - adults take notice of it too. To emphasize the personalization theme, we personalized the emails that we sent out to invite customers to our booth at the show also.
Mark has written about embedding personalized images into the body of an email before in his blog post How to Acquire Customers and Influence People with Personalization. For the Discovery LightTM, we decided to go a step further and create personalized landing pages for each recipient, a feature available in the ExactTarget email software that we use, that the customers would reach if they clicked on a link in the email. The behavior of the individual customers who clicked on the link is trackable through the landing page.
With these powerful tools we were able to generate interest in our exhibit at the show, the brand new Discovery LightTM web site, and the value of personalization all at the same time.
If you would like to see my photos from my short but interesting trip to the show, please click here - Graph Expo '08.

ExactTarget recommends putting your brand and a call to action into a 4-5 inch square (between 288 and 360 pixels) at the upper left corner of the email. This is the most viewed part of the message. Our logo, company name and color scheme are comfortably in the critical area, so I would say our brand is where it is supposed to be.

I usually use my MP3 player for rocking out, but the other day I was able to use mine (a Sansa c240) to get some work done.
