Did I expose myself to information-theft via possible malware on iPad by opening an e-mail in Safari?
It appears the site is distributing malware. If you opened the page on your computer you should first install a good antivirus/antimalware program, try Sophos which is good and free. If it was on your iPad (as your tag suggests) there's probably a bit less cause for alarm as there is currently no known virus which can infect an iPad.

Next it's probably a good idea to change all of your passwords, most importantly your AppleID as it stores your confidential information and credit card data. You can manage your apple id here.