This postcard was posted on the 9th Wonders message board. It contained a secret message from Richard Drucker to Hana. The fans had to figure out that on the backside, the handwritten message was actually a JavaScript. Adding the code to a html document would deliver this message from Richard Drucker, who didn't want to be contacted by Hana:
"You are playing with fire. Please stop your investigations into my past!"
9th Wonders Message Boards
Hana's Blog
Hana SMS messages (HeroesWiki.com)
Drucker Blog Entries (HeroesClues.com)