Dust is an annoying, grey substance that builds up where you live, but is electrostaticly attracted to screens and electronics. I hate it. It makes the house smell stale, it gums up the cooling fans, it gets stuck where it's hard to clean, and I can never get all of it. What the hell is that crap, anyway?
Dust varies from place to place, but it almost always contains skin cells and hairs from you, textile fibers from your clothing, and cosmic debris filtered down to tiny particles by the atmosphere. Whereupon it coats every surface, especially the electrically charged ones.
When it's really important to keep out dust, clean rooms are invented. The room is totally sealed, then over pressured with known-clean air. If any leaks develop, air blasts through it, repulsing any dust that seeks to come in. To stay that way, all humans in the area have to wear bunny suits so as to not contribute to the problem.
Okay, but that costs a pretty penny. What's a cheaper way to keep my dwelling free of that grey crap?
Two words: Air Flow. Have a (ludicrous) fan suck air through a filter, and blast it through every room. The dust would be trapped in the filter, so I'd never have to dust again. I would, however, have to frequently change the filter.
(My house does in fact have a central air system fed by a filtered-intake, and it does in fact trap a large amount of dust. Doesn't stop more from evading it, grumble grumble.)