@Beep yup all true, the advice you give covers all websites. No security is perfect and prevention/regular maintenance (inc windows update, java, acrobat,flash, antivirus etc) is definately important. If I had a tenner every time I heard somebody say 'well it worked fine before' or 'I've never had an issue' just after being infected I'd be rich.
I maintain servers with lots of users on them myself. I'm patching against SQL injection attacks (for instance) regularly.
Prevention happens at both ends, the weakest link is the most insecure.
Security with Cakewalk will be no different than the store and probably better. As I say everybody does it now and have been for some time. I never allow websites to store my credit card details BTW except PayPal and amazon. People who log into websites themselves need to be responsible for their own security BTW, if they don't feel that way they will soon learn the hard way.
People alway think forums are always inherily insecure, the reality is that the authentication will probably be taken away from the forums and done elsewhere via a provider which will make it MORE secure (better code and infrastructure ). Cake I'm sure are well aware of security implications and will make it as tight as possible.
BTW the login transaction only happens once. Staying logged into a site for long periods really doesn't not decrease you security unless somebody has remote control of your machine. Vast majority of hacks are not done that way as it's very inefficient.