My idea of zooming in on a web page is that everything becomes bigger. Everything is still the same but just bigger. This is because I feel it should be like zooming on a camera or telescope (where I think the term comes from).
The zooming feature is required for many reasons and should be allowed but there seems to be two distinct styles. ux.stackexchange.com performs as I would expect and everything becomes larger. www.smashingmagazine.com and Twitter Bootstrap change as I zoom.
For a user on a large screen (desktop), what would they expect from a zoom function. Do users expect zoom to keep the same elements and placements and just make things larger?
Is it bad design for elements to be hidden or moved when zooming (www.smashingmagazine.com)? Or is it just a choice between using zoom for more detail (maps/images) or readability?