I'm a fellow Outlook user myself. I didn't read the article that you mentioned in your post, but it sounds like it may have been a typo. In my e-mail system I have an @Action folder but I also have an @Computer context list under Tasks. I've never heard of an @Computer folder before; he may have meant @Action.
If all I need to do is reply to the e-mail message but it's going to take longer than 2 minutes, I move it to the @Action folder. E-mail from friends to which I want to reply falls under this category.
If the message requires some other form of action then I use my context lists. For example, when I get an automated notification that my credit card statement is available online, I add "Pay credit card bill" to my @Computer list, and I toss the e-mail. If the e-mail needs to be kept as support material, I keep it in a folder called "@Action Support", and I clean out this folder during weekly reviews.
I create folders under Inbox for my general reference materials the same way that I do for my paper filing system--one folder per topic, person, or project. Outlook automatically alphabetizes the list. That works best for me.
I hope this helps.