Late reply, but it was a simple tutorial, probably meant for first-time owners. Looks like that helpful section was just meant to help some kind of sales operation which quickly folded (the site only got archived once before disappearing)
Also, I'm not really sure this part in particular was the best advice:
Wipe with a dry cloth: Be sure to get every nook and cranny when wiping with a dry cloth. On delicate areas, blowing away the dust is the preferred method of cleaning.
First of all, there's a good chance the average new owner is going to think that blowing with one's breath is the way to go, inadvertently adding moisture. Second, why blow dust around when you can get a mini-vacuum in there and remove it for good?
As long as there's no loose, vulnerable, broken parts, I'd tend to think vacuuming in most areas would be preferable. That said, I'd think you'd want to avoid sticking a strong vacuum directly on EM relays and that sort of thing.