Can you edit that date?
The reason is, the Sony PRS-650 shows the last 3 books added on the home page. So the ability to change the date added, allows one to affect which books show up.
There is a small utility over in the Sony Reader section that allows you to change the date, even to a date in the future (so that adding more books does not affect what shows up on the home page).
What I really wish for, is a setup that would automatically change the date back to some date in the past, once the books is read.